diff --git a/src/ocrmypdf/_validation.py b/src/ocrmypdf/_validation.py
index 5a533fa9..fe15a84e 100644
--- a/src/ocrmypdf/_validation.py
+++ b/src/ocrmypdf/_validation.py
@@ -63,9 +63,7 @@ def check_options_languages(options):
         options.language = [DEFAULT_LANGUAGE]
         system_lang = locale.getlocale()[0]
         if system_lang and not system_lang.startswith('en'):
-            log.debug(
-                "No language specified; assuming --language %s" % DEFAULT_LANGUAGE
-            )
+            log.debug("No language specified; assuming --language %s", DEFAULT_LANGUAGE)
 
     # Support v2.x "eng+deu" language syntax
     if '+' in options.language[0]:
diff --git a/tests/test_validation.py b/tests/test_validation.py
index 5465a580..7d70f367 100644
--- a/tests/test_validation.py
+++ b/tests/test_validation.py
@@ -153,6 +153,7 @@ def test_language_warning(caplog):
         assert opts.language == ['eng']
         assert '' in caplog.text
 
+    opts = make_opts(language=None)
     with patch(
         'ocrmypdf._validation.locale.getlocale', return_value=('fr_FR', 'UTF-8')
     ):