diff --git a/lib/tasks/stt-task.js b/lib/tasks/stt-task.js
index 7e24cb38..9d922ebe 100644
--- a/lib/tasks/stt-task.js
+++ b/lib/tasks/stt-task.js
@@ -37,6 +37,10 @@ class SttTask extends Task {
 
       /* let credentials be supplied in the recognizer object at runtime */
       this.sttCredentials = setSpeechCredentialsAtRuntime(recognizer);
+
+      if (!Array.isArray(this.data.recognizer.altLanguages)) {
+        this.data.recognizer.altLanguages = [];
+      }
     } else {
       this.data.recognizer = {hints: [], altLanguages: []};
     }