diff --git a/doc_src/conf.py b/doc_src/conf.py
index abcab794f..def07e916 100644
--- a/doc_src/conf.py
+++ b/doc_src/conf.py
@@ -93,12 +93,14 @@ source_suffix = ".rst"
 # The master toctree document.
 master_doc = "index"
 
-# The language for content autogenerated by Sphinx. Refer to documentation
-# for a list of supported languages.
+# The languages this uses, also used for content autogenerated by Sphinx.
 #
 # 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
+#
+# It also sets the html lang= attribute which would be useful to e.g. screenreaders.
+# Currently we only have english.
+language = "en"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.