diff --git a/spacy/compat.py b/spacy/compat.py
index 2a551a831..b3019f45b 100644
--- a/spacy/compat.py
+++ b/spacy/compat.py
@@ -6,6 +6,8 @@ import ftfy
 import sys
 import ujson
 
+import thinc.neural.util
+
 try:
     import cPickle as pickle
 except ImportError:
@@ -32,6 +34,7 @@ copy_reg = copy_reg
 CudaStream = CudaStream
 cupy = cupy
 fix_text = ftfy.fix_text
+copy_array = thinc.neural.util.copy_array
 
 is_python2 = six.PY2
 is_python3 = six.PY3
@@ -71,3 +74,16 @@ def is_config(python2=None, python3=None, windows=None, linux=None, osx=None):
             (windows == None or windows == is_windows) and
             (linux == None or linux == is_linux) and
             (osx == None or osx == is_osx))
+
+
+def normalize_string_keys(old):
+    '''Given a dictionary, make sure keys are unicode strings, not bytes.'''
+    new = {}
+    for key, value in old:
+        if isinstance(key, bytes_):
+            new[key.decode('utf8')] = value
+        else:
+            new[key] = value
+    return new
+
+
diff --git a/spacy/util.py b/spacy/util.py
index 273293c24..dabceb4a8 100644
--- a/spacy/util.py
+++ b/spacy/util.py
@@ -22,6 +22,7 @@ import ujson
 
 from .symbols import ORTH
 from .compat import cupy, CudaStream, path2str, basestring_, input_, unicode_
+from .compat import copy_array, normalize_string_keys
 
 
 LANGUAGES = {}
@@ -243,6 +244,12 @@ def itershuffle(iterable, bufsize=1000):
         raise StopIteration
 
 
+_PRINT_ENV = False
+def set_env_log(value):
+    global _PRINT_ENV
+    _PRINT_ENV = value
+
+
 def env_opt(name, default=None):
     if type(default) is float:
         type_convert = float
@@ -250,14 +257,17 @@ def env_opt(name, default=None):
         type_convert = int
     if 'SPACY_' + name.upper() in os.environ:
         value = type_convert(os.environ['SPACY_' + name.upper()])
-        print(name, "=", repr(value), "via", "$SPACY_" + name.upper())
+        if _PRINT_ENV:
+            print(name, "=", repr(value), "via", "$SPACY_" + name.upper())
         return value
     elif name in os.environ:
         value = type_convert(os.environ[name])
-        print(name, "=", repr(value), "via", '$' + name)
+        if _PRINT_ENV:
+            print(name, "=", repr(value), "via", '$' + name)
         return value
     else:
-        print(name, '=', repr(default), "by default")
+        if _PRINT_ENV:
+            print(name, '=', repr(default), "by default")
         return default
 
 
@@ -451,7 +461,9 @@ def model_to_bytes(model):
     i = 0
     for layer in queue:
         if hasattr(layer, '_mem'):
-            weights.append({'dims': dict(getattr(layer, '_dims', {})), 'params': []})
+            weights.append({
+                'dims': normalize_string_keys(getattr(layer, '_dims', {})),
+                'params': []})
             if hasattr(layer, 'seed'):
                 weights[-1]['seed'] = layer.seed
 
@@ -488,7 +500,7 @@ def model_from_bytes(model, bytes_data):
                 setattr(layer, dim, value)
             for param in weights[i]['params']:
                 dest = getattr(layer, param['name'])
-                dest[:] = param['value']
+                copy_array(dest, param['value'])
             i += 1
         if hasattr(layer, '_layers'):
             queue.extend(layer._layers)