diff --git a/kagi.el b/kagi.el
index d3a3ec0..ee2957a 100644
--- a/kagi.el
+++ b/kagi.el
@@ -418,7 +418,7 @@ ENGINE is the name of a supported summarizer engine, as
 defined in `kagi--summarizer-engines'."
 
   (let* ((kagi-summarizer-default-language
-          (downcase (or language kagi-summarizer-default-language)))
+          (upcase (or language kagi-summarizer-default-language)))
          (kagi-summarizer-engine
           (downcase (or engine kagi-summarizer-engine))))
     (if-let* ((response (if (kagi--url-p text-or-url)