diff --git a/pytorch_transformers/modeling_xlm.py b/pytorch_transformers/modeling_xlm.py
index 5a659e02f92..035787a97b2 100644
--- a/pytorch_transformers/modeling_xlm.py
+++ b/pytorch_transformers/modeling_xlm.py
@@ -44,6 +44,8 @@ XLM_PRETRAINED_MODEL_ARCHIVE_MAP = {
     'xlm-mlm-xnli15-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-xnli15-1024-pytorch_model.bin",
     'xlm-clm-enfr-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-clm-enfr-1024-pytorch_model.bin",
     'xlm-clm-ende-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-clm-ende-1024-pytorch_model.bin",
+    'xlm-mlm-17-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-pytorch_model.json",
+    'xlm-mlm-100-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-pytorch_model.json",
 }
 XLM_PRETRAINED_CONFIG_ARCHIVE_MAP = {
     'xlm-mlm-en-2048': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-en-2048-config.json",
@@ -54,6 +56,8 @@ XLM_PRETRAINED_CONFIG_ARCHIVE_MAP = {
     'xlm-mlm-xnli15-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-xnli15-1024-config.json",
     'xlm-clm-enfr-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-clm-enfr-1024-config.json",
     'xlm-clm-ende-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-clm-ende-1024-config.json",
+    'xlm-mlm-17-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-config.json",
+    'xlm-mlm-100-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-config.json",
 }
 
 
@@ -114,6 +118,7 @@ class XLMConfig(PretrainedConfig):
                  causal=False,
                  asm=False,
                  n_langs=1,
+                 use_lang_emb=True,
                  max_position_embeddings=512,
                  embed_init_std=2048 ** -0.5,
                  layer_norm_eps=1e-12,
@@ -157,6 +162,7 @@ class XLMConfig(PretrainedConfig):
             self.causal = causal
             self.asm = asm
             self.n_langs = n_langs
+            self.use_lang_emb = use_lang_emb
             self.layer_norm_eps = layer_norm_eps
             self.bos_index = bos_index
             self.eos_index = eos_index
@@ -488,7 +494,7 @@ class XLMModel(XLMPreTrainedModel):
 
     """
     ATTRIBUTES = ['encoder', 'eos_index', 'pad_index',  # 'with_output', 
-                  'n_langs', 'n_words', 'dim', 'n_layers', 'n_heads', 
+                  'n_langs', 'use_lang_emb', 'n_words', 'dim', 'n_layers', 'n_heads', 
                   'hidden_dim', 'dropout', 'attention_dropout', 'asm',
                   'asm_cutoffs', 'asm_div_value']
 
@@ -507,6 +513,7 @@ class XLMModel(XLMPreTrainedModel):
 
         # dictionary / languages
         self.n_langs = config.n_langs
+        self.use_lang_emb = config.use_lang_emb
         self.n_words = config.n_words
         self.eos_index = config.eos_index
         self.pad_index = config.pad_index
@@ -529,7 +536,7 @@ class XLMModel(XLMPreTrainedModel):
         self.position_embeddings = nn.Embedding(config.max_position_embeddings, self.dim)
         if config.sinusoidal_embeddings:
             create_sinusoidal_embeddings(config.max_position_embeddings, self.dim, out=self.position_embeddings.weight)
-        if config.n_langs > 1:
+        if config.n_langs > 1 and config.use_lang_emb:
             self.lang_embeddings = nn.Embedding(self.n_langs, self.dim)
         self.embeddings = nn.Embedding(self.n_words, self.dim, padding_idx=self.pad_index)
         self.layer_norm_emb = nn.LayerNorm(self.dim, eps=config.layer_norm_eps)
@@ -628,7 +635,7 @@ class XLMModel(XLMPreTrainedModel):
         # embeddings
         tensor = self.embeddings(input_ids)
         tensor = tensor + self.position_embeddings(position_ids).expand_as(tensor)
-        if langs is not None:
+        if langs is not None and self.use_lang_emb:
             tensor = tensor + self.lang_embeddings(langs)
         if token_type_ids is not None:
             tensor = tensor + self.embeddings(token_type_ids)
diff --git a/pytorch_transformers/tests/tokenization_bert_test.py b/pytorch_transformers/tests/tokenization_bert_test.py
index aaca746d469..1111683ecc5 100644
--- a/pytorch_transformers/tests/tokenization_bert_test.py
+++ b/pytorch_transformers/tests/tokenization_bert_test.py
@@ -41,8 +41,8 @@ class BertTokenizationTest(CommonTestCases.CommonTokenizerTester):
         with open(self.vocab_file, "w", encoding='utf-8') as vocab_writer:
             vocab_writer.write("".join([x + "\n" for x in vocab_tokens]))
 
-    def get_tokenizer(self):
-        return self.tokenizer_class.from_pretrained(self.tmpdirname)
+    def get_tokenizer(self, **kwargs):
+        return BertTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def get_input_output_texts(self):
         input_text = u"UNwant\u00E9d,running"
diff --git a/pytorch_transformers/tests/tokenization_dilbert_test.py b/pytorch_transformers/tests/tokenization_dilbert_test.py
index 30268db2166..42f80609981 100644
--- a/pytorch_transformers/tests/tokenization_dilbert_test.py
+++ b/pytorch_transformers/tests/tokenization_dilbert_test.py
@@ -27,8 +27,8 @@ class DistilBertTokenizationTest(BertTokenizationTest):
 
     tokenizer_class = DistilBertTokenizer
 
-    def get_tokenizer(self):
-        return DistilBertTokenizer.from_pretrained(self.tmpdirname)
+    def get_tokenizer(self, **kwargs):
+        return DistilBertTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def test_sequence_builders(self):
         tokenizer = DistilBertTokenizer.from_pretrained("distilbert-base-uncased")
diff --git a/pytorch_transformers/tests/tokenization_gpt2_test.py b/pytorch_transformers/tests/tokenization_gpt2_test.py
index da7028c27d7..252dbfe6f47 100644
--- a/pytorch_transformers/tests/tokenization_gpt2_test.py
+++ b/pytorch_transformers/tests/tokenization_gpt2_test.py
@@ -44,8 +44,9 @@ class GPT2TokenizationTest(CommonTestCases.CommonTokenizerTester):
         with open(self.merges_file, "w") as fp:
             fp.write("\n".join(merges))
 
-    def get_tokenizer(self):
-        return GPT2Tokenizer.from_pretrained(self.tmpdirname, **self.special_tokens_map)
+    def get_tokenizer(self, **kwargs):
+        kwargs.update(self.special_tokens_map)
+        return GPT2Tokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def get_input_output_texts(self):
         input_text = u"lower newer"
diff --git a/pytorch_transformers/tests/tokenization_openai_test.py b/pytorch_transformers/tests/tokenization_openai_test.py
index bb354f3fb77..6b86416d2d6 100644
--- a/pytorch_transformers/tests/tokenization_openai_test.py
+++ b/pytorch_transformers/tests/tokenization_openai_test.py
@@ -45,8 +45,8 @@ class OpenAIGPTTokenizationTest(CommonTestCases.CommonTokenizerTester):
         with open(self.merges_file, "w") as fp:
             fp.write("\n".join(merges))
 
-    def get_tokenizer(self):
-        return OpenAIGPTTokenizer.from_pretrained(self.tmpdirname)
+    def get_tokenizer(self, **kwargs):
+        return OpenAIGPTTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def get_input_output_texts(self):
         input_text = u"lower newer"
diff --git a/pytorch_transformers/tests/tokenization_roberta_test.py b/pytorch_transformers/tests/tokenization_roberta_test.py
index a8f940ae432..5f9b65a7a30 100644
--- a/pytorch_transformers/tests/tokenization_roberta_test.py
+++ b/pytorch_transformers/tests/tokenization_roberta_test.py
@@ -43,8 +43,9 @@ class RobertaTokenizationTest(CommonTestCases.CommonTokenizerTester):
         with open(self.merges_file, "w") as fp:
             fp.write("\n".join(merges))
 
-    def get_tokenizer(self):
-        return RobertaTokenizer.from_pretrained(self.tmpdirname, **self.special_tokens_map)
+    def get_tokenizer(self, **kwargs):
+        kwargs.update(self.special_tokens_map)
+        return RobertaTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def get_input_output_texts(self):
         input_text = u"lower newer"
diff --git a/pytorch_transformers/tests/tokenization_tests_commons.py b/pytorch_transformers/tests/tokenization_tests_commons.py
index ebcf6f48d87..6578c5c3a56 100644
--- a/pytorch_transformers/tests/tokenization_tests_commons.py
+++ b/pytorch_transformers/tests/tokenization_tests_commons.py
@@ -49,23 +49,32 @@ class CommonTestCases:
         def tearDown(self):
             shutil.rmtree(self.tmpdirname)
 
-        def get_tokenizer(self):
+        def get_tokenizer(self, **kwargs):
             raise NotImplementedError
 
         def get_input_output_texts(self):
             raise NotImplementedError
 
         def test_save_and_load_tokenizer(self):
+            # safety check on max_len default value so we are sure the test works
             tokenizer = self.get_tokenizer()
+            self.assertNotEqual(tokenizer.max_len, 42)
+
+            # Now let's start the test
+            tokenizer = self.get_tokenizer(max_len=42)
 
             before_tokens = tokenizer.encode(u"He is very happy, UNwant\u00E9d,running")
 
             with TemporaryDirectory() as tmpdirname:
                 tokenizer.save_pretrained(tmpdirname)
-                tokenizer = tokenizer.from_pretrained(tmpdirname)
+                tokenizer = self.tokenizer_class.from_pretrained(tmpdirname)
 
-            after_tokens = tokenizer.encode(u"He is very happy, UNwant\u00E9d,running")
-            self.assertListEqual(before_tokens, after_tokens)
+                after_tokens = tokenizer.encode(u"He is very happy, UNwant\u00E9d,running")
+                self.assertListEqual(before_tokens, after_tokens)
+
+                self.assertEqual(tokenizer.max_len, 42)
+                tokenizer = self.tokenizer_class.from_pretrained(tmpdirname, max_len=43)
+                self.assertEqual(tokenizer.max_len, 43)
 
         def test_pickle_tokenizer(self):
             tokenizer = self.get_tokenizer()
diff --git a/pytorch_transformers/tests/tokenization_transfo_xl_test.py b/pytorch_transformers/tests/tokenization_transfo_xl_test.py
index fbd06cf47e7..f881cf1d2b4 100644
--- a/pytorch_transformers/tests/tokenization_transfo_xl_test.py
+++ b/pytorch_transformers/tests/tokenization_transfo_xl_test.py
@@ -37,8 +37,9 @@ class TransfoXLTokenizationTest(CommonTestCases.CommonTokenizerTester):
         with open(self.vocab_file, "w", encoding='utf-8') as vocab_writer:
             vocab_writer.write("".join([x + "\n" for x in vocab_tokens]))
 
-    def get_tokenizer(self):
-        return TransfoXLTokenizer.from_pretrained(self.tmpdirname, lower_case=True)
+    def get_tokenizer(self, **kwargs):
+        kwargs['lower_case'] = True
+        return TransfoXLTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def get_input_output_texts(self):
         input_text = u"<unk> UNwanted , running"
diff --git a/pytorch_transformers/tests/tokenization_xlm_test.py b/pytorch_transformers/tests/tokenization_xlm_test.py
index ede77a1f988..43f1e0c5dd7 100644
--- a/pytorch_transformers/tests/tokenization_xlm_test.py
+++ b/pytorch_transformers/tests/tokenization_xlm_test.py
@@ -44,8 +44,8 @@ class XLMTokenizationTest(CommonTestCases.CommonTokenizerTester):
         with open(self.merges_file, "w") as fp:
             fp.write("\n".join(merges))
 
-    def get_tokenizer(self):
-        return XLMTokenizer.from_pretrained(self.tmpdirname)
+    def get_tokenizer(self, **kwargs):
+        return XLMTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def get_input_output_texts(self):
         input_text = u"lower newer"
diff --git a/pytorch_transformers/tests/tokenization_xlnet_test.py b/pytorch_transformers/tests/tokenization_xlnet_test.py
index 9feab7c0bdf..c603ce55f9d 100644
--- a/pytorch_transformers/tests/tokenization_xlnet_test.py
+++ b/pytorch_transformers/tests/tokenization_xlnet_test.py
@@ -35,8 +35,8 @@ class XLNetTokenizationTest(CommonTestCases.CommonTokenizerTester):
         tokenizer = XLNetTokenizer(SAMPLE_VOCAB, keep_accents=True)
         tokenizer.save_pretrained(self.tmpdirname)
 
-    def get_tokenizer(self):
-        return XLNetTokenizer.from_pretrained(self.tmpdirname)
+    def get_tokenizer(self, **kwargs):
+        return XLNetTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
     def get_input_output_texts(self):
         input_text = u"This is a test"
diff --git a/pytorch_transformers/tokenization_bert.py b/pytorch_transformers/tokenization_bert.py
index 92f027038df..46f839c6270 100644
--- a/pytorch_transformers/tokenization_bert.py
+++ b/pytorch_transformers/tokenization_bert.py
@@ -63,6 +63,23 @@ PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
     'bert-base-cased-finetuned-mrpc': 512,
 }
 
+PRETRAINED_INIT_CONFIGURATION = {
+    'bert-base-uncased': {'do_lower_case': True},
+    'bert-large-uncased': {'do_lower_case': True},
+    'bert-base-cased': {'do_lower_case': False},
+    'bert-large-cased': {'do_lower_case': False},
+    'bert-base-multilingual-uncased': {'do_lower_case': True},
+    'bert-base-multilingual-cased': {'do_lower_case': False},
+    'bert-base-chinese': {'do_lower_case': False},
+    'bert-base-german-cased': {'do_lower_case': False},
+    'bert-large-uncased-whole-word-masking': {'do_lower_case': True},
+    'bert-large-cased-whole-word-masking': {'do_lower_case': False},
+    'bert-large-uncased-whole-word-masking-finetuned-squad': {'do_lower_case': True},
+    'bert-large-cased-whole-word-masking-finetuned-squad': {'do_lower_case': False},
+    'bert-base-cased-finetuned-mrpc': {'do_lower_case': False},
+}
+
+
 def load_vocab(vocab_file):
     """Loads a vocabulary file into a dictionary."""
     vocab = collections.OrderedDict()
@@ -100,6 +117,7 @@ class BertTokenizer(PreTrainedTokenizer):
 
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
+    pretrained_init_configuration = PRETRAINED_INIT_CONFIGURATION
     max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
 
     def __init__(self, vocab_file, do_lower_case=True, do_basic_tokenize=True, never_split=None,
@@ -202,24 +220,6 @@ class BertTokenizer(PreTrainedTokenizer):
                 index += 1
         return (vocab_file,)
 
-    @classmethod
-    def from_pretrained(cls, pretrained_model_name_or_path, *inputs, **kwargs):
-        """ Instantiate a BertTokenizer from pre-trained vocabulary files.
-        """
-        if pretrained_model_name_or_path in PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES:
-            if '-cased' in pretrained_model_name_or_path and kwargs.get('do_lower_case', True):
-                logger.warning("The pre-trained model you are loading is a cased model but you have not set "
-                               "`do_lower_case` to False. We are setting `do_lower_case=False` for you but "
-                               "you may want to check this behavior.")
-                kwargs['do_lower_case'] = False
-            elif '-cased' not in pretrained_model_name_or_path and not kwargs.get('do_lower_case', True):
-                logger.warning("The pre-trained model you are loading is an uncased model but you have set "
-                               "`do_lower_case` to False. We are setting `do_lower_case=True` for you "
-                               "but you may want to check this behavior.")
-                kwargs['do_lower_case'] = True
-
-        return super(BertTokenizer, cls)._from_pretrained(pretrained_model_name_or_path, *inputs, **kwargs)
-
 
 class BasicTokenizer(object):
     """Runs basic tokenization (punctuation splitting, lower casing, etc.)."""
diff --git a/pytorch_transformers/tokenization_transfo_xl.py b/pytorch_transformers/tokenization_transfo_xl.py
index c603ba695c1..66bc01c1bb0 100644
--- a/pytorch_transformers/tokenization_transfo_xl.py
+++ b/pytorch_transformers/tokenization_transfo_xl.py
@@ -95,7 +95,8 @@ class TransfoXLTokenizer(PreTrainedTokenizer):
             # in a library like ours, at all.
             vocab_dict = torch.load(pretrained_vocab_file)
             for key, value in vocab_dict.items():
-                self.__dict__[key] = value
+                if key not in self.__dict__:
+                    self.__dict__[key] = value
 
         if vocab_file is not None:
             self.build_vocab()
diff --git a/pytorch_transformers/tokenization_utils.py b/pytorch_transformers/tokenization_utils.py
index 9d814f704f7..56ccdbcb915 100644
--- a/pytorch_transformers/tokenization_utils.py
+++ b/pytorch_transformers/tokenization_utils.py
@@ -20,6 +20,7 @@ import logging
 import os
 import json
 import six
+import copy
 from io import open
 
 from .file_utils import cached_path
@@ -28,6 +29,7 @@ logger = logging.getLogger(__name__)
 
 SPECIAL_TOKENS_MAP_FILE = 'special_tokens_map.json'
 ADDED_TOKENS_FILE = 'added_tokens.json'
+TOKENIZER_CONFIG_FILE = 'tokenizer_config.json'
 
 class PreTrainedTokenizer(object):
     """ Base class for all tokenizers.
@@ -40,6 +42,7 @@ class PreTrainedTokenizer(object):
         - ``vocab_files_names``: a python ``dict`` with, as keys, the ``__init__`` keyword name of each vocabulary file required by the model, and as associated values, the filename for saving the associated file (string).
         - ``pretrained_vocab_files_map``: a python ``dict of dict`` the high-level keys being the ``__init__`` keyword name of each vocabulary file required by the model, the low-level being the `short-cut-names` (string) of the pretrained models with, as associated values, the `url` (string) to the associated pretrained vocabulary file.
         - ``max_model_input_sizes``: a python ``dict`` with, as keys, the `short-cut-names` (string) of the pretrained models, and as associated values, the maximum length of the sequence inputs of this model, or None if the model has no maximum input size.
+        - ``pretrained_init_configuration``: a python ``dict`` with, as keys, the `short-cut-names` (string) of the pretrained models, and as associated values, a dictionnary of specific arguments to pass to the ``__init__``method of the tokenizer class for this pretrained model when loading the tokenizer with the ``from_pretrained()`` method.
 
     Parameters:
 
@@ -61,6 +64,7 @@ class PreTrainedTokenizer(object):
     """
     vocab_files_names = {}
     pretrained_vocab_files_map = {}
+    pretrained_init_configuration = {}
     max_model_input_sizes = {}
 
     SPECIAL_TOKENS_ATTRIBUTES = ["bos_token", "eos_token", "unk_token", "sep_token",
@@ -166,12 +170,15 @@ class PreTrainedTokenizer(object):
         self._additional_special_tokens = []
 
         self.max_len = max_len if max_len is not None else int(1e12)
-        self.max_len_single_sentence = self.max_len
-        self.max_len_sentences_pair = self.max_len
 
+        # Added tokens
         self.added_tokens_encoder = {}
         self.added_tokens_decoder = {}
 
+        # inputs and kwargs for saving and re-loading (see ``from_pretrained`` and ``save_pretrained``)
+        self.init_inputs = ()
+        self.init_kwargs = {}
+
         for key, value in kwargs.items():
             if key in self.SPECIAL_TOKENS_ATTRIBUTES:
                 if key == 'additional_special_tokens':
@@ -231,17 +238,20 @@ class PreTrainedTokenizer(object):
 
 
     @classmethod
-    def _from_pretrained(cls, pretrained_model_name_or_path, *inputs, **kwargs):
+    def _from_pretrained(cls, pretrained_model_name_or_path, *init_inputs, **kwargs):
         cache_dir = kwargs.pop('cache_dir', None)
         force_download = kwargs.pop('force_download', False)
         proxies = kwargs.pop('proxies', None)
 
         s3_models = list(cls.max_model_input_sizes.keys())
         vocab_files = {}
+        init_configuration = {}
         if pretrained_model_name_or_path in s3_models:
             # Get the vocabulary from AWS S3 bucket
             for file_id, map_list in cls.pretrained_vocab_files_map.items():
                 vocab_files[file_id] = map_list[pretrained_model_name_or_path]
+            if cls.pretrained_init_configuration and pretrained_model_name_or_path in cls.pretrained_init_configuration:
+                init_configuration = cls.pretrained_init_configuration[pretrained_model_name_or_path]
         else:
             # Get the vocabulary from local files
             logger.info(
@@ -264,15 +274,17 @@ class PreTrainedTokenizer(object):
                 vocab_files[file_id] = full_file_name
 
             # Look for the additional tokens files
-            all_vocab_files_names = {'added_tokens_file': ADDED_TOKENS_FILE,
-                                     'special_tokens_map_file': SPECIAL_TOKENS_MAP_FILE}
+            additional_files_names = {'added_tokens_file': ADDED_TOKENS_FILE,
+                                      'special_tokens_map_file': SPECIAL_TOKENS_MAP_FILE,
+                                      'tokenizer_config_file': TOKENIZER_CONFIG_FILE,
+                                      }
 
             # If a path to a file was provided, get the parent directory
             saved_directory = pretrained_model_name_or_path
             if os.path.exists(saved_directory) and not os.path.isdir(saved_directory):
                 saved_directory = os.path.dirname(saved_directory)
 
-            for file_id, file_name in all_vocab_files_names.items():
+            for file_id, file_name in additional_files_names.items():
                 full_file_name = os.path.join(saved_directory, file_name)
                 if not os.path.exists(full_file_name):
                     logger.info("Didn't find file {}. We won't load it.".format(full_file_name))
@@ -315,28 +327,46 @@ class PreTrainedTokenizer(object):
                 logger.info("loading file {} from cache at {}".format(
                     file_path, resolved_vocab_files[file_id]))
 
+        # Prepare tokenizer initialization kwargs
+        # Did we saved some inputs and kwargs to reload ?
+        tokenizer_config_file = resolved_vocab_files.pop('tokenizer_config_file', None)
+        if tokenizer_config_file is not None:
+            init_kwargs = json.load(open(tokenizer_config_file, encoding="utf-8"))
+            saved_init_inputs = init_kwargs.pop('init_inputs', ())
+            if not init_inputs:
+                init_inputs = saved_init_inputs
+        else:
+            init_kwargs = init_configuration
+
+        # Update with newly provided kwargs
+        init_kwargs.update(kwargs)
+
         # Set max length if needed
         if pretrained_model_name_or_path in cls.max_model_input_sizes:
             # if we're using a pretrained model, ensure the tokenizer
             # wont index sequences longer than the number of positional embeddings
             max_len = cls.max_model_input_sizes[pretrained_model_name_or_path]
             if max_len is not None and isinstance(max_len, (int, float)):
-                kwargs['max_len'] = min(kwargs.get('max_len', int(1e12)), max_len)
+                init_kwargs['max_len'] = min(init_kwargs.get('max_len', int(1e12)), max_len)
 
-        # Merge resolved_vocab_files arguments in kwargs.
+        # Merge resolved_vocab_files arguments in init_kwargs.
         added_tokens_file = resolved_vocab_files.pop('added_tokens_file', None)
         special_tokens_map_file = resolved_vocab_files.pop('special_tokens_map_file', None)
         for args_name, file_path in resolved_vocab_files.items():
-            if args_name not in kwargs:
-                kwargs[args_name] = file_path
+            if args_name not in init_kwargs:
+                init_kwargs[args_name] = file_path
         if special_tokens_map_file is not None:
             special_tokens_map = json.load(open(special_tokens_map_file, encoding="utf-8"))
             for key, value in special_tokens_map.items():
-                if key not in kwargs:
-                    kwargs[key] = value
+                if key not in init_kwargs:
+                    init_kwargs[key] = value
 
         # Instantiate tokenizer.
-        tokenizer = cls(*inputs, **kwargs)
+        tokenizer = cls(*init_inputs, **init_kwargs)
+
+        # Save inputs and kwargs for saving and re-loading with ``save_pretrained``
+        tokenizer.init_inputs = init_inputs
+        tokenizer.init_kwargs = init_kwargs
 
         # Add supplementary tokens.
         if added_tokens_file is not None:
@@ -349,8 +379,13 @@ class PreTrainedTokenizer(object):
 
 
     def save_pretrained(self, save_directory):
-        """ Save the tokenizer vocabulary files (with added tokens) and the
-            special-tokens-to-class-attributes-mapping to a directory.
+        """ Save the tokenizer vocabulary files together with:
+                - added tokens,
+                - special-tokens-to-class-attributes-mapping,
+                - tokenizer instantiation positional and keywords inputs (e.g. do_lower_case for Bert).
+
+            This won't save modifications other than (added tokens and special token mapping) you may have
+            applied to the tokenizer after the instantion (e.g. modifying tokenizer.do_lower_case after creation).
 
             This method make sure the full tokenizer can then be re-loaded using the :func:`~pytorch_transformers.PreTrainedTokenizer.from_pretrained` class method.
         """
@@ -360,6 +395,15 @@ class PreTrainedTokenizer(object):
 
         special_tokens_map_file = os.path.join(save_directory, SPECIAL_TOKENS_MAP_FILE)
         added_tokens_file = os.path.join(save_directory, ADDED_TOKENS_FILE)
+        tokenizer_config_file = os.path.join(save_directory, TOKENIZER_CONFIG_FILE)
+
+        tokenizer_config = copy.deepcopy(self.init_kwargs)
+        tokenizer_config['init_inputs'] = copy.deepcopy(self.init_inputs)
+        for file_id in self.vocab_files_names.keys():
+            tokenizer_config.pop(file_id, None)
+
+        with open(tokenizer_config_file, 'w', encoding='utf-8') as f:
+            f.write(json.dumps(tokenizer_config, ensure_ascii=False))
 
         with open(special_tokens_map_file, 'w', encoding='utf-8') as f:
             f.write(json.dumps(self.special_tokens_map, ensure_ascii=False))
@@ -566,7 +610,7 @@ class PreTrainedTokenizer(object):
     def _convert_token_to_id(self, token):
         raise NotImplementedError
 
-    def encode(self, text, text_pair=None, add_special_tokens=False):
+    def encode(self, text, text_pair=None, add_special_tokens=False, **kwargs):
         """
         Converts a string in a sequence of ids (integer), using the tokenizer and vocabulary.
         
@@ -577,15 +621,16 @@ class PreTrainedTokenizer(object):
             text_pair: Optional second sequence to be encoded.
             add_special_tokens: if set to ``True``, the sequences will be encoded with the special tokens relative
                 to their model.
+            **kwargs: passed to the `self.tokenize()` method
         """
         if text_pair is None:
             if add_special_tokens:
-                return self.add_special_tokens_single_sentence(self.convert_tokens_to_ids(self.tokenize(text)))
+                return self.add_special_tokens_single_sentence(self.convert_tokens_to_ids(self.tokenize(text, **kwargs)))
             else:
-                return self.convert_tokens_to_ids(self.tokenize(text))
+                return self.convert_tokens_to_ids(self.tokenize(text, **kwargs))
 
-        first_sentence_tokens = [self._convert_token_to_id(token) for token in self.tokenize(text)]
-        second_sentence_tokens = [self._convert_token_to_id(token) for token in self.tokenize(text_pair)]
+        first_sentence_tokens = [self._convert_token_to_id(token) for token in self.tokenize(text, **kwargs)]
+        second_sentence_tokens = [self._convert_token_to_id(token) for token in self.tokenize(text_pair, **kwargs)]
 
         if add_special_tokens:
             return self.add_special_tokens_sentences_pair(first_sentence_tokens, second_sentence_tokens)
diff --git a/pytorch_transformers/tokenization_xlm.py b/pytorch_transformers/tokenization_xlm.py
index 2b930458bbf..d14acb39c63 100644
--- a/pytorch_transformers/tokenization_xlm.py
+++ b/pytorch_transformers/tokenization_xlm.py
@@ -20,8 +20,12 @@ import json
 import logging
 import os
 import re
+import sys
+import unicodedata
 from io import open
 
+import sacremoses as sm
+
 from .tokenization_utils import PreTrainedTokenizer
 from .tokenization_bert import BasicTokenizer
 
@@ -43,6 +47,8 @@ PRETRAINED_VOCAB_FILES_MAP = {
         'xlm-mlm-xnli15-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-xnli15-1024-vocab.json",
         'xlm-clm-enfr-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-clm-enfr-1024-vocab.json",
         'xlm-clm-ende-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-clm-ende-1024-vocab.json",
+        'xlm-mlm-17-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-vocab.json",
+        'xlm-mlm-100-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-vocab.json",
     },
     'merges_file':
     {
@@ -54,6 +60,8 @@ PRETRAINED_VOCAB_FILES_MAP = {
         'xlm-mlm-xnli15-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-xnli15-1024-merges.txt",
         'xlm-clm-enfr-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-enfr-1024-merges.txt",
         'xlm-clm-ende-1024': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-ende-1024-merges.txt",
+        'xlm-mlm-17-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-merges.txt",
+        'xlm-mlm-100-1280': "https://s3.amazonaws.com/models.huggingface.co/bert/xlm-mlm-17-1280-merges.txt",
     },
 }
 
@@ -66,6 +74,342 @@ PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
     'xlm-mlm-xnli15-1024': 512,
     'xlm-clm-enfr-1024': 512,
     'xlm-clm-ende-1024': 512,
+    'xlm-mlm-17-1280': 512,
+    'xlm-mlm-100-1280': 512,
+}
+
+PRETRAINED_INIT_CONFIGURATION = {
+    'xlm-mlm-en-2048': {"do_lowercase_and_remove_accent": True},
+    'xlm-mlm-ende-1024': { "do_lowercase_and_remove_accent": True,
+                            "id2lang": { "0": "de",
+                                        "1": "en"},
+                           "lang2id": { "de": 0,
+                                        "en": 1 }},
+    'xlm-mlm-enfr-1024': { "do_lowercase_and_remove_accent": True,
+                           "id2lang": { "0": "en",
+                                        "1": "fr"},
+                           "lang2id": { "en": 0,
+                                        "fr": 1 }},
+    'xlm-mlm-enro-1024': { "do_lowercase_and_remove_accent": True,
+                           "id2lang": { "0": "en",
+                                        "1": "ro"},
+                           "lang2id": { "en": 0,
+                                        "ro": 1 }},
+    'xlm-mlm-tlm-xnli15-1024': { "do_lowercase_and_remove_accent": True,
+                                 "id2lang": {   "0": "ar",
+                                                "1": "bg",
+                                                "2": "de",
+                                                "3": "el",
+                                                "4": "en",
+                                                "5": "es",
+                                                "6": "fr",
+                                                "7": "hi",
+                                                "8": "ru",
+                                                "9": "sw",
+                                                "10": "th",
+                                                "11": "tr",
+                                                "12": "ur",
+                                                "13": "vi",
+                                                "14": "zh"},
+                                 "lang2id": {   "ar": 0,
+                                                "bg": 1,
+                                                "de": 2,
+                                                "el": 3,
+                                                "en": 4,
+                                                "es": 5,
+                                                "fr": 6,
+                                                "hi": 7,
+                                                "ru": 8,
+                                                "sw": 9,
+                                                "th": 10,
+                                                "tr": 11,
+                                                "ur": 12,
+                                                "vi": 13,
+                                                "zh": 14 }},
+    'xlm-mlm-xnli15-1024': { "do_lowercase_and_remove_accent": True,
+                             "id2lang": {   "0": "ar",
+                                                "1": "bg",
+                                                "2": "de",
+                                                "3": "el",
+                                                "4": "en",
+                                                "5": "es",
+                                                "6": "fr",
+                                                "7": "hi",
+                                                "8": "ru",
+                                                "9": "sw",
+                                                "10": "th",
+                                                "11": "tr",
+                                                "12": "ur",
+                                                "13": "vi",
+                                                "14": "zh"},
+                                 "lang2id": {   "ar": 0,
+                                                "bg": 1,
+                                                "de": 2,
+                                                "el": 3,
+                                                "en": 4,
+                                                "es": 5,
+                                                "fr": 6,
+                                                "hi": 7,
+                                                "ru": 8,
+                                                "sw": 9,
+                                                "th": 10,
+                                                "tr": 11,
+                                                "ur": 12,
+                                                "vi": 13,
+                                                "zh": 14 }},
+    'xlm-clm-enfr-1024': { "do_lowercase_and_remove_accent": True,
+                           "id2lang": { "0": "en",
+                                        "1": "fr"},
+                           "lang2id": { "en": 0,
+                                        "fr": 1 }},
+    'xlm-clm-ende-1024': { "do_lowercase_and_remove_accent": True,
+                           "id2lang": { "0": "de",
+                                        "1": "en"},
+                           "lang2id": { "de": 0,
+                                        "en": 1 }},
+    'xlm-mlm-17-1280': {"do_lowercase_and_remove_accent": False,
+                        "id2lang": {
+                            "0": "ar",
+                            "1": "de",
+                            "2": "en",
+                            "3": "es",
+                            "4": "fr",
+                            "5": "hi",
+                            "6": "it",
+                            "7": "ja",
+                            "8": "ko",
+                            "9": "nl",
+                            "10": "pl",
+                            "11": "pt",
+                            "12": "ru",
+                            "13": "sv",
+                            "14": "tr",
+                            "15": "vi",
+                            "16": "zh"
+                        },
+                        "lang2id": {
+                            "ar": 0,
+                            "de": 1,
+                            "en": 2,
+                            "es": 3,
+                            "fr": 4,
+                            "hi": 5,
+                            "it": 6,
+                            "ja": 7,
+                            "ko": 8,
+                            "nl": 9,
+                            "pl": 10,
+                            "pt": 11,
+                            "ru": 12,
+                            "sv": 13,
+                            "tr": 14,
+                            "vi": 15,
+                            "zh": 16}},
+    'xlm-mlm-100-1280': {"do_lowercase_and_remove_accent": False,
+                        "id2lang": {
+                            "0": "af",
+                            "1": "als",
+                            "2": "am",
+                            "3": "an",
+                            "4": "ang",
+                            "5": "ar",
+                            "6": "arz",
+                            "7": "ast",
+                            "8": "az",
+                            "9": "bar",
+                            "10": "be",
+                            "11": "bg",
+                            "12": "bn",
+                            "13": "br",
+                            "14": "bs",
+                            "15": "ca",
+                            "16": "ceb",
+                            "17": "ckb",
+                            "18": "cs",
+                            "19": "cy",
+                            "20": "da",
+                            "21": "de",
+                            "22": "el",
+                            "23": "en",
+                            "24": "eo",
+                            "25": "es",
+                            "26": "et",
+                            "27": "eu",
+                            "28": "fa",
+                            "29": "fi",
+                            "30": "fr",
+                            "31": "fy",
+                            "32": "ga",
+                            "33": "gan",
+                            "34": "gl",
+                            "35": "gu",
+                            "36": "he",
+                            "37": "hi",
+                            "38": "hr",
+                            "39": "hu",
+                            "40": "hy",
+                            "41": "ia",
+                            "42": "id",
+                            "43": "is",
+                            "44": "it",
+                            "45": "ja",
+                            "46": "jv",
+                            "47": "ka",
+                            "48": "kk",
+                            "49": "kn",
+                            "50": "ko",
+                            "51": "ku",
+                            "52": "la",
+                            "53": "lb",
+                            "54": "lt",
+                            "55": "lv",
+                            "56": "mk",
+                            "57": "ml",
+                            "58": "mn",
+                            "59": "mr",
+                            "60": "ms",
+                            "61": "my",
+                            "62": "nds",
+                            "63": "ne",
+                            "64": "nl",
+                            "65": "nn",
+                            "66": "no",
+                            "67": "oc",
+                            "68": "pl",
+                            "69": "pt",
+                            "70": "ro",
+                            "71": "ru",
+                            "72": "scn",
+                            "73": "sco",
+                            "74": "sh",
+                            "75": "si",
+                            "76": "simple",
+                            "77": "sk",
+                            "78": "sl",
+                            "79": "sq",
+                            "80": "sr",
+                            "81": "sv",
+                            "82": "sw",
+                            "83": "ta",
+                            "84": "te",
+                            "85": "th",
+                            "86": "tl",
+                            "87": "tr",
+                            "88": "tt",
+                            "89": "uk",
+                            "90": "ur",
+                            "91": "uz",
+                            "92": "vi",
+                            "93": "war",
+                            "94": "wuu",
+                            "95": "yi",
+                            "96": "zh",
+                            "97": "zh_classical",
+                            "98": "zh_min_nan",
+                            "99": "zh_yue"
+                        },
+                        "lang2id": {
+                            "af": 0,
+                            "als": 1,
+                            "am": 2,
+                            "an": 3,
+                            "ang": 4,
+                            "ar": 5,
+                            "arz": 6,
+                            "ast": 7,
+                            "az": 8,
+                            "bar": 9,
+                            "be": 10,
+                            "bg": 11,
+                            "bn": 12,
+                            "br": 13,
+                            "bs": 14,
+                            "ca": 15,
+                            "ceb": 16,
+                            "ckb": 17,
+                            "cs": 18,
+                            "cy": 19,
+                            "da": 20,
+                            "de": 21,
+                            "el": 22,
+                            "en": 23,
+                            "eo": 24,
+                            "es": 25,
+                            "et": 26,
+                            "eu": 27,
+                            "fa": 28,
+                            "fi": 29,
+                            "fr": 30,
+                            "fy": 31,
+                            "ga": 32,
+                            "gan": 33,
+                            "gl": 34,
+                            "gu": 35,
+                            "he": 36,
+                            "hi": 37,
+                            "hr": 38,
+                            "hu": 39,
+                            "hy": 40,
+                            "ia": 41,
+                            "id": 42,
+                            "is": 43,
+                            "it": 44,
+                            "ja": 45,
+                            "jv": 46,
+                            "ka": 47,
+                            "kk": 48,
+                            "kn": 49,
+                            "ko": 50,
+                            "ku": 51,
+                            "la": 52,
+                            "lb": 53,
+                            "lt": 54,
+                            "lv": 55,
+                            "mk": 56,
+                            "ml": 57,
+                            "mn": 58,
+                            "mr": 59,
+                            "ms": 60,
+                            "my": 61,
+                            "nds": 62,
+                            "ne": 63,
+                            "nl": 64,
+                            "nn": 65,
+                            "no": 66,
+                            "oc": 67,
+                            "pl": 68,
+                            "pt": 69,
+                            "ro": 70,
+                            "ru": 71,
+                            "scn": 72,
+                            "sco": 73,
+                            "sh": 74,
+                            "si": 75,
+                            "simple": 76,
+                            "sk": 77,
+                            "sl": 78,
+                            "sq": 79,
+                            "sr": 80,
+                            "sv": 81,
+                            "sw": 82,
+                            "ta": 83,
+                            "te": 84,
+                            "th": 85,
+                            "tl": 86,
+                            "tr": 87,
+                            "tt": 88,
+                            "uk": 89,
+                            "ur": 90,
+                            "uz": 91,
+                            "vi": 92,
+                            "war": 93,
+                            "wuu": 94,
+                            "yi": 95,
+                            "zh": 96,
+                            "zh_classical": 97,
+                            "zh_min_nan": 98,
+                            "zh_yue": 99
+                        }},
 }
 
 def get_pairs(word):
@@ -80,62 +424,145 @@ def get_pairs(word):
         prev_char = char
     return pairs
 
-def text_standardize(text):
+
+def lowercase_and_remove_accent(text):
     """
-    fixes some issues the spacy tokenizer had on books corpus
-    also does some whitespace standardization
+    Lowercase and strips accents from a piece of text based on
+    https://github.com/facebookresearch/XLM/blob/master/tools/lowercase_and_remove_accent.py
     """
-    text = text.replace('—', '-')
-    text = text.replace('–', '-')
-    text = text.replace('―', '-')
+    text = ' '.join(text)
+    text = text.lower()
+    text = unicodedata.normalize("NFD", text)
+    output = []
+    for char in text:
+        cat = unicodedata.category(char)
+        if cat == "Mn":
+            continue
+        output.append(char)
+    return "".join(output).lower().split(' ')
+
+
+def replace_unicode_punct(text):
+    '''
+    Port of https://github.com/moses-smt/mosesdecoder/blob/master/scripts/tokenizer/replace-unicode-punctuation.perl
+    '''
+    text = text.replace('，', ',')
+    text = re.sub(r'。\s*', '. ', text)
+    text = text.replace('、', ',')
+    text = text.replace('”', '"')
+    text = text.replace('“', '"')
+    text = text.replace('∶', ':')
+    text = text.replace('：', ':')
+    text = text.replace('？', '?')
+    text = text.replace('《', '"')
+    text = text.replace('》', '"')
+    text = text.replace('）', ')')
+    text = text.replace('！', '!')
+    text = text.replace('（', '(')
+    text = text.replace('；', ';')
+    text = text.replace('１', '"')
+    text = text.replace('」', '"')
+    text = text.replace('「', '"')
+    text = text.replace('０', '0')
+    text = text.replace('３', '3')
+    text = text.replace('２', '2')
+    text = text.replace('５', '5')
+    text = text.replace('６', '6')
+    text = text.replace('９', '9')
+    text = text.replace('７', '7')
+    text = text.replace('８', '8')
+    text = text.replace('４', '4')
+    text = re.sub(r'．\s*', '. ', text)
+    text = text.replace('～', '~')
+    text = text.replace('’', '\'')
     text = text.replace('…', '...')
-    text = text.replace('´', "'")
-    text = re.sub(r'''(-+|~+|!+|"+|;+|\?+|\++|,+|\)+|\(+|\\+|\/+|\*+|\[+|\]+|}+|{+|\|+|_+)''', r' \1 ', text)
-    text = re.sub(r'\s*\n\s*', ' \n ', text)
-    text = re.sub(r'[^\S\n]+', ' ', text)
-    return text.strip()
+    text = text.replace('━', '-')
+    text = text.replace('〈', '<')
+    text = text.replace('〉', '>')
+    text = text.replace('【', '[')
+    text = text.replace('】', ']')
+    text = text.replace('％', '%')
+    return text
+
+
+def remove_non_printing_char(text):
+    '''
+    Port of https://github.com/moses-smt/mosesdecoder/blob/master/scripts/tokenizer/remove-non-printing-char.perl
+    '''
+    output = []
+    for char in text:
+        cat = unicodedata.category(char)
+        if cat.startswith('C'):
+            continue
+        output.append(char)
+    return "".join(output)
+
+
+def romanian_preprocessing(text):
+    '''Sennrich's WMT16 scripts for Romanian preprocessing, used by model `xlm-mlm-enro-1024`'''
+    # https://github.com/rsennrich/wmt16-scripts/blob/master/preprocess/normalise-romanian.py
+    text = text.replace("\u015e", "\u0218").replace("\u015f", "\u0219")
+    text = text.replace("\u0162", "\u021a").replace("\u0163", "\u021b")
+    # https://github.com/rsennrich/wmt16-scripts/blob/master/preprocess/remove-diacritics.py
+    text = text.replace("\u0218", "S").replace("\u0219", "s") #s-comma
+    text = text.replace("\u021a", "T").replace("\u021b", "t") #t-comma
+    text = text.replace("\u0102", "A").replace("\u0103", "a")
+    text = text.replace("\u00C2", "A").replace("\u00E2", "a")
+    text = text.replace("\u00CE", "I").replace("\u00EE", "i")
+    return text
+
 
 class XLMTokenizer(PreTrainedTokenizer):
     """
-    BPE tokenizer for XLM, adapted from OpenAI BPE tokenizer. Peculiarities:
+    BPE tokenizer for XLM
 
-        - lower case all inputs
+        - Moses preprocessing & tokenization for most supported languages
 
-        - uses `SpaCy tokenizer <https://spacy.io/api/tokenizer/>`_ and \
-        `ftfy <https://ftfy.readthedocs.io/en/latest/>`_ for pre-BPE tokenization if they are installed, \
-        fallback to BERT's BasicTokenizer if not.
+        - Language specific tokenization for Chinese (Jieba), Japanese (KyTea) and Thai (PyThaiNLP)
+
+        - (optionally) lower case & normalize all inputs text
 
         - argument ``special_tokens`` and function ``set_special_tokens``, can be used to add additional symbols \
-        (ex: "__classify__") to a vocabulary.
+        (ex: "__classify__") to a vocabulary
+        
+        - `lang2id` attribute maps the languages supported by the model with their ids if provided (automatically set for pretrained vocabularies)
+
+        - `id2lang` attributes does reverse mapping if provided (automatically set for pretrained vocabularies)
+
+        - `do_lowercase_and_remove_accent` controle lower casing and accent (automatically set for pretrained vocabularies)
     """
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
+    pretrained_init_configuration = PRETRAINED_INIT_CONFIGURATION
     max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
 
     def __init__(self, vocab_file, merges_file, unk_token="<unk>", bos_token="<s>",
                  sep_token="</s>", pad_token="<pad>", cls_token="</s>",
                  mask_token="<special1>", additional_special_tokens=["<special0>",
                  "<special1>", "<special2>", "<special3>", "<special4>", "<special5>",
-                 "<special6>", "<special7>", "<special8>", "<special9>"], **kwargs):
+                 "<special6>", "<special7>", "<special8>", "<special9>"],
+                 lang2id=None, id2lang=None, do_lowercase_and_remove_accent=True,
+                 **kwargs):
         super(XLMTokenizer, self).__init__(unk_token=unk_token, bos_token=bos_token,
                                            sep_token=sep_token, pad_token=pad_token,
                                            cls_token=cls_token, mask_token=mask_token,
                                            additional_special_tokens=additional_special_tokens,
                                            **kwargs)
 
-        self.max_len_single_sentence = self.max_len - 2  # take into account special tokens
-        self.max_len_sentences_pair = self.max_len - 3  # take into account special tokens
+        # cache of sm.MosesPunctNormalizer instance
+        self.cache_moses_punct_normalizer = dict()
+        # cache of sm.MosesTokenizer instance
+        self.cache_moses_tokenizer = dict()
+        self.lang_with_custom_tokenizer = set(['zh', 'th', 'ja'])
+        # True for current supported model (v1.2.0), False for XLM-17 & 100
+        self.do_lowercase_and_remove_accent = do_lowercase_and_remove_accent
+        self.lang2id = lang2id
+        self.id2lang = id2lang
+        if lang2id is not None and id2lang is not None:
+            assert len(lang2id) == len(id2lang)
 
-        try:
-            import ftfy
-            from spacy.lang.en import English
-            _nlp = English()
-            self.nlp = _nlp.Defaults.create_tokenizer(_nlp)
-            self.fix_text = ftfy.fix_text
-        except ImportError:
-            logger.warning("ftfy or spacy is not installed using BERT BasicTokenizer instead of SpaCy & ftfy.")
-            self.nlp = BasicTokenizer(do_lower_case=True)
-            self.fix_text = None
+        self.ja_word_tokenizer = None
+        self.zh_word_tokenizer = None
 
         self.encoder = json.load(open(vocab_file, encoding="utf-8"))
         self.decoder = {v:k for k,v in self.encoder.items()}
@@ -144,6 +571,43 @@ class XLMTokenizer(PreTrainedTokenizer):
         self.bpe_ranks = dict(zip(merges, range(len(merges))))
         self.cache = {}
 
+    def moses_punct_norm(self, text, lang):
+        if lang not in self.cache_moses_punct_normalizer:
+            punct_normalizer = sm.MosesPunctNormalizer(lang=lang)
+            self.cache_moses_punct_normalizer[lang] = punct_normalizer
+        else:
+            punct_normalizer = self.cache_moses_punct_normalizer[lang]
+        return punct_normalizer.normalize(text)
+
+    def moses_tokenize(self, text, lang):
+        if lang not in self.cache_moses_tokenizer:
+            moses_tokenizer = sm.MosesTokenizer(lang=lang)
+            self.cache_moses_tokenizer[lang] = moses_tokenizer
+        else:
+            moses_tokenizer = self.cache_moses_tokenizer[lang]
+        return moses_tokenizer.tokenize(text, return_str=False, escape=False)
+
+    def moses_pipeline(self, text, lang):
+        text = replace_unicode_punct(text)
+        text = self.moses_punct_norm(text, lang)
+        text = remove_non_printing_char(text)
+        return text
+
+    def ja_tokenize(self, text):
+        if self.ja_word_tokenizer is None:
+            try:
+                import Mykytea
+                self.ja_word_tokenizer = Mykytea.Mykytea('-model %s/local/share/kytea/model.bin' % os.path.expanduser('~'))
+            except (AttributeError, ImportError) as e:
+                logger.error("Make sure you install KyTea (https://github.com/neubig/kytea) and it's python wrapper (https://github.com/chezou/Mykytea-python) with the following steps")
+                logger.error("1. git clone git@github.com:neubig/kytea.git && cd kytea")
+                logger.error("2. autoreconf -i")
+                logger.error("3. ./configure --prefix=$HOME/local")
+                logger.error("4. make && make install")
+                logger.error("5. pip install kytea")
+                raise e
+        return list(self.ja_word_tokenizer.getWS(text))
+
     @property
     def vocab_size(self):
         return len(self.encoder)
@@ -191,19 +655,86 @@ class XLMTokenizer(PreTrainedTokenizer):
         self.cache[token] = word
         return word
 
-    def _tokenize(self, text):
-        """ Tokenize a string. """
-        split_tokens = []
-        if self.fix_text is None:
-            # Using BERT's BasicTokenizer
-            text = self.nlp.tokenize(text)
-            for token in text:
-                split_tokens.extend([t for t in self.bpe(token).split(' ')])
+    def _tokenize(self, text, lang='en', bypass_tokenizer=False):
+        """
+        Tokenize a string given language code. For Chinese, Japanese and Thai, we use a language specific tokenizerself. Otherwise, we use Moses.
+
+        Details of tokenization:
+        - [sacremoses](https://github.com/alvations/sacremoses): port of Moses
+            - Install with `pip install sacremoses`
+        - [pythainlp](https://github.com/PyThaiNLP/pythainlp): Thai tokenizer
+            - Install with `pip install pythainlp`
+        - [kytea](https://github.com/chezou/Mykytea-python): Japanese tokenizer, wrapper of [KyTea](https://github.com/neubig/kytea)
+            - Install with the following steps:
+            ```
+            git clone git@github.com:neubig/kytea.git && cd kytea
+            autoreconf -i
+            ./configure --prefix=$HOME/local
+            make && make install
+            pip install kytea
+            ```
+        - [jieba](https://github.com/fxsjy/jieba): Chinese tokenizer *
+            - Install with `pip install jieba`
+
+        \* The original XLM used [Stanford Segmenter](https://nlp.stanford.edu/software/stanford-segmenter-2018-10-16.zip).
+        However, the wrapper (`nltk.tokenize.stanford_segmenter`) is slow due to JVM overhead, and it will be deprecated.
+        Jieba is a lot faster and pip-installable. Note there is some mismatch with the Stanford Segmenter. It should be fine
+        if you fine-tune the model with Chinese supervisionself. If you want the same exact behaviour, use the original XLM
+        [preprocessing script](https://github.com/facebookresearch/XLM/tree/master/tools) to tokenize the sentence externally,
+        and set `bypass_tokenizer=True` to bypass the tokenizer.
+
+        Args:
+            - lang: ISO language code (default = 'en') (string). Languages should belong of the model supported languages. However, we don't enforce it.
+            - bypass_tokenizer: Allow users to preprocess and tokenize the sentences externally (default = False)  (bool). If True, we only apply BPE.
+
+        Returns:
+            List of tokens.
+        """
+        if lang and self.lang2id and lang not in self.lang2id:
+            logger.error("Supplied language code not found in lang2id mapping. Please check that your language is supported by the loaded pretrained model.")
+        if bypass_tokenizer:
+            text = text.split()
+        elif lang not in self.lang_with_custom_tokenizer:
+            text = self.moses_pipeline(text, lang=lang)
+            # TODO: make sure we are using `xlm-mlm-enro-1024`, since XLM-100 doesn't have this step
+            if lang == 'ro':
+                text = romanian_preprocessing(text)
+            text = self.moses_tokenize(text, lang=lang)
+        elif lang == 'th':
+            text = self.moses_pipeline(text, lang=lang)
+            try:
+                if 'pythainlp' not in sys.modules:
+                    from pythainlp.tokenize import word_tokenize as th_word_tokenize
+            except (AttributeError, ImportError) as e:
+                logger.error("Make sure you install PyThaiNLP (https://github.com/PyThaiNLP/pythainlp) with the following steps")
+                logger.error("1. pip install pythainlp")
+                raise e
+            text = th_word_tokenize(text)
+        elif lang == 'zh':
+            try:
+                if 'jieba' not in sys.modules:
+                    import jieba
+            except (AttributeError, ImportError) as e:
+                logger.error("Make sure you install Jieba (https://github.com/fxsjy/jieba) with the following steps")
+                logger.error("1. pip install jieba")
+                raise e
+            text = ' '.join(jieba.cut(text))
+            text = self.moses_pipeline(text, lang=lang)
+            text = text.split()
+        elif lang == 'ja':
+            text = self.moses_pipeline(text, lang=lang)
+            text = self.ja_tokenize(text)
         else:
-            # Using SpaCy & ftfy (original tokenization process of OpenAI GPT)
-            text = self.nlp(text_standardize(self.fix_text(text)))
-            for token in text:
-                split_tokens.extend([t for t in self.bpe(token.text.lower()).split(' ')])
+            raise ValueError('It should not reach here')
+
+        if self.do_lowercase_and_remove_accent and not bypass_tokenizer:
+            text = lowercase_and_remove_accent(text)
+
+        split_tokens = []
+        for token in text:
+            if token:
+                split_tokens.extend([t for t in self.bpe(token).split(' ')])
+
         return split_tokens
 
     def _convert_token_to_id(self, token):
diff --git a/pytorch_transformers/tokenization_xlnet.py b/pytorch_transformers/tokenization_xlnet.py
index ac7231bb680..bf9b9dc782f 100644
--- a/pytorch_transformers/tokenization_xlnet.py
+++ b/pytorch_transformers/tokenization_xlnet.py
@@ -61,7 +61,7 @@ class XLNetTokenizer(PreTrainedTokenizer):
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
     max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
 
-    def __init__(self, vocab_file, max_len=None,
+    def __init__(self, vocab_file,
                  do_lower_case=False, remove_space=True, keep_accents=False,
                  bos_token="<s>", eos_token="</s>", unk_token="<unk>", sep_token="<sep>",
                  pad_token="<pad>", cls_token="<cls>", mask_token="<mask>",
diff --git a/requirements.txt b/requirements.txt
index 76532d18a59..01dca79d23b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,4 +9,6 @@ requests
 # For OpenAI GPT
 regex
 # For XLNet
-sentencepiece
\ No newline at end of file
+sentencepiece
+# For XLM
+sacremoses
\ No newline at end of file
diff --git a/setup.py b/setup.py
index c9f80fc224a..29797222681 100644
--- a/setup.py
+++ b/setup.py
@@ -55,7 +55,8 @@ setup(
                       'requests',
                       'tqdm',
                       'regex',
-                      'sentencepiece'],
+                      'sentencepiece',
+                      'sacremoses'],
     entry_points={
       'console_scripts': [
         "pytorch_transformers=pytorch_transformers.__main__:main",