diff --git a/spacy/language.py b/spacy/language.py
index e85854735..ae8aa4560 100644
--- a/spacy/language.py
+++ b/spacy/language.py
@@ -46,10 +46,6 @@ class Language(object):
     def suffix(string):
         return string[-3:]
 
-    @staticmethod
-    def prob(string):
-        return -30
-
     @staticmethod
     def cluster(string):
         return 0
@@ -119,7 +115,8 @@ class Language(object):
         return 0
 
     @classmethod
-    def default_lex_attrs(cls):
+    def default_lex_attrs(cls, *args, **kwargs):
+        oov_prob = kwargs.get('oov_prob', -20)
         return {
             attrs.LOWER: cls.lower,
             attrs.NORM: cls.norm,
@@ -127,8 +124,7 @@ class Language(object):
             attrs.PREFIX: cls.prefix,
             attrs.SUFFIX: cls.suffix,
             attrs.CLUSTER: cls.cluster,
-            attrs.PROB: lambda string: -10.0,
-    
+            attrs.PROB: lambda string: oov_prob,
             attrs.IS_ALPHA: cls.is_alpha,
             attrs.IS_ASCII: cls.is_ascii,
             attrs.IS_DIGIT: cls.is_digit,
@@ -159,7 +155,12 @@ class Language(object):
     @classmethod
     def default_vocab(cls, package, get_lex_attr=None):
         if get_lex_attr is None:
-            get_lex_attr = cls.default_lex_attrs()
+            if package.has_file('vocab', 'oov_prob'):
+                with package.open(('vocab', 'oov_prob')) as file_:
+                    oov_prob = float(file_.read().strip())
+                get_lex_attr = cls.default_lex_attrs(oov_prob=oov_prob)
+            else:
+                get_lex_attr = cls.default_lex_attrs()
         if hasattr(package, 'dir_path'):
             return Vocab.from_package(package, get_lex_attr=get_lex_attr)
         else:
diff --git a/spacy/vocab.pyx b/spacy/vocab.pyx
index 5946d8169..a0a07f305 100644
--- a/spacy/vocab.pyx
+++ b/spacy/vocab.pyx
@@ -110,21 +110,20 @@ cdef class Vocab:
         # TODO: This is hopelessly broken. The state is transferred as just 
         # a temp directory! We then fail to clean this up. This method therefore
         # only pretends to work. What we need to do is form an archive file.
-        raise NotImplementedError
-        #tmp_dir = tempfile.mkdtemp()
-        #lex_loc = path.join(tmp_dir, 'lexemes.bin')
-        #str_loc = path.join(tmp_dir, 'strings.json')
-        #vec_loc = path.join(tmp_dir, 'vec.bin')
+        tmp_dir = tempfile.mkdtemp()
+        lex_loc = path.join(tmp_dir, 'lexemes.bin')
+        str_loc = path.join(tmp_dir, 'strings.json')
+        vec_loc = path.join(tmp_dir, 'vec.bin')
 
-        #self.dump(lex_loc)
-        #with io.open(str_loc, 'w', encoding='utf8') as file_:
-        #    self.strings.dump(file_)
+        self.dump(lex_loc)
+        with io.open(str_loc, 'w', encoding='utf8') as file_:
+            self.strings.dump(file_)
 
-        #self.dump_vectors(vec_loc)
-        #
-        #state = (str_loc, lex_loc, vec_loc, self.morphology, self.get_lex_attr,
-        #         self.serializer_freqs, self.data_dir)
-        #return (unpickle_vocab, state, None, None)
+        self.dump_vectors(vec_loc)
+        
+        state = (str_loc, lex_loc, vec_loc, self.morphology, self.get_lex_attr,
+                 self.serializer_freqs, self.data_dir)
+        return (unpickle_vocab, state, None, None)
 
     cdef const LexemeC* get(self, Pool mem, unicode string) except NULL:
         '''Get a pointer to a LexemeC from the lexicon, creating a new Lexeme