diff --git a/src/transcriber.rs b/src/transcriber.rs
index 95bdc48..dab30e2 100644
--- a/src/transcriber.rs
+++ b/src/transcriber.rs
@@ -90,7 +90,10 @@ impl Transcriber {
         if let Some(lang) = language {
             fp.set_language(Some(lang));
         } else {
-            fp.set_detect_language(true);
+            // Setting language to None (null) triggers whisper's auto-detection AND transcription.
+            // set_detect_language(true) is WRONG: it causes whisper to return 0 after language
+            // detection without transcribing (see whisper.cpp: `if (detect_language) return 0`).
+            fp.set_language(None);
         }
 
         fp.set_translate(task == "translate");