diff --git a/data/voxforge/voxforge.py b/data/voxforge/voxforge.py
index b86b0f004..b7cc38bdb 100644
--- a/data/voxforge/voxforge.py
+++ b/data/voxforge/voxforge.py
@@ -11,6 +11,7 @@ from __future__ import print_function
 
 import os
 import codecs
+import datetime
 import soundfile
 import json
 import argparse
diff --git a/data_utils/speech.py b/data_utils/speech.py
index 0cea88730..e64109dc8 100644
--- a/data_utils/speech.py
+++ b/data_utils/speech.py
@@ -3,6 +3,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import numpy as np
 from data_utils.audio import AudioSegment