diff --git a/doc/manual-src/ru/conf.py.in b/doc/manual-src/ru/conf.py.in
index 350b9ee7..15f8de0a 100644
--- a/doc/manual-src/ru/conf.py.in
+++ b/doc/manual-src/ru/conf.py.in
@@ -54,7 +54,7 @@ release = '@PACKAGE_VERSION@'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
-#language = None
+language = 'ru'
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used: