Works around a DicationRecognizer.StopRecording() issue. This https://issuetracker.unity3d.com/issues/wsa-windows-speech-dictationrecognizer-throws-assertion-failed-on-expression-succeeded-hr-when-user-cancels-the-input claims it is fixed, but it is clearly not.

Author: Joost van Schaik

Assets/HoloToolkit/Input/Scripts/InputSources/DictationInputManager.cs

@@ -101,6 +101,7 @@ protected override void OnDestroy()
 
         #endregion // Unity Methods
 
+
         /// <summary>
         /// Turns on the dictation recognizer and begins recording audio from the default microphone.
         /// </summary>
@@ -167,6 +168,14 @@ public static IEnumerator StartRecording(GameObject listener = null, float initi
         /// </summary>
         public static IEnumerator StopRecording()
         {
+            yield return Instance.StopRecordingInternal();
+        }
+
+        /// <summary>
+        /// Ends the recording session.
+        /// </summary>
+        private IEnumerator StopRecordingInternal()
+        {
 #if UNITY_WSA || UNITY_STANDALONE_WIN
             if (!IsListening || isTransitioning)
             {
@@ -190,16 +199,21 @@ public static IEnumerator StopRecording()
                 dictationRecognizer.Stop();
             }
 
+            StartCoroutine(FinishStopRecording());
+#else
+            return null;
+#endif
+        }
+
+        private IEnumerator FinishStopRecording()
+        {
             while (dictationRecognizer.Status == SpeechSystemStatus.Running)
             {
                 yield return null;
             }
 
             PhraseRecognitionSystem.Restart();
             isTransitioning = false;
-#else
-            return null;
-#endif
         }
 
         #region Dictation Recognizer Callbacks