diff --git a/docs/source/conf.py b/docs/source/conf.py
index 85d0a23..a7b5f01 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -101,7 +101,7 @@
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-language = None
+language = "en"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.