diff --git a/deepmoji/filter_utils.py b/deepmoji/filter_utils.py
index c82ffee..afc8986 100644
--- a/deepmoji/filter_utils.py
+++ b/deepmoji/filter_utils.py
@@ -140,7 +140,7 @@ def shorten_word(word):
 
     # only shorten ASCII words
     try:
-        word.decode('ascii')
+        word.encode().decode('ascii')
     except (UnicodeDecodeError, UnicodeEncodeError) as e:
         return word
 
diff --git a/deepmoji/word_generator.py b/deepmoji/word_generator.py
index f3e7ce3..2937151 100644
--- a/deepmoji/word_generator.py
+++ b/deepmoji/word_generator.py
@@ -64,7 +64,7 @@ def get_words(self, sentence):
             that is not allowed.
         """
 
-        if not isinstance(sentence, unicode):
+        if not isinstance(sentence, str):
             raise ValueError("All sentences should be Unicode-encoded!")
         sentence = sentence.strip().lower()
 
@@ -96,7 +96,7 @@ def check_ascii(self, word):
         """ Returns whether a word is ASCII """
 
         try:
-            word.decode('ascii')
+            word.encode().decode('ascii')
             return True
         except (UnicodeDecodeError, UnicodeEncodeError):
             return False