diff --git a/src/process/twitter_process.py b/src/process/twitter_process.py
index 9cf90f1..6870413 100644
--- a/src/process/twitter_process.py
+++ b/src/process/twitter_process.py
@@ -121,7 +121,8 @@ def select_user_sample(user_dir: str = './data/twitter/user/') -> None:
     users = load_users(user_dir)
 
     # Filter by language first
-    users = [u for u in users if any(lang in u.lang for lang in {'en', 'zh', 'ja'})]
+    users = [u for u in users if u.lang is not None and
+             any(lang in u.lang for lang in {'en', 'zh', 'ja'})]
 
     # Find most popular, and exclude them from the random sample
     most_popular = users[:500]