diff --git a/sphinx/application.py b/sphinx/application.py
index 74aa2d630..c29152075 100644
--- a/sphinx/application.py
+++ b/sphinx/application.py
@@ -350,13 +350,15 @@ class Sphinx:
                       else __('finished with problems'))
             if self._warncount:
                 if self.warningiserror:
-                    msg = __('build %s, %s warning (with warnings treated as errors).',
-                             'build %s, %s warnings (with warnings treated as errors).',
-                             self._warncount)
+                    if self._warncount == 1:
+                        msg = __('build %s, %s warning (with warnings treated as errors).')
+                    else:
+                        msg = __('build %s, %s warnings (with warnings treated as errors).')
                 else:
-                    msg = __('build %s, %s warning.',
-                             'build %s, %s warnings.',
-                             self._warncount)
+                    if self._warncount == 1:
+                        msg = __('build %s, %s warning.')
+                    else:
+                        msg = __('build %s, %s warnings.')
 
                 logger.info(bold(msg % (status, self._warncount)))
             else: