speech updates for supported rest api

Author: eric-urban

articles/ai-services/speech-service/includes/quickstarts/speech-to-text-basics/intro.md

@@ -11,6 +11,6 @@ ms.author: eur
 In this quickstart, you create and run an application to recognize and transcribe speech to text in real-time. 
 
 > [!TIP]
-> For fast transcription of audio files, consider using the [fast transcription API.](/azure/ai-services/speech-service/fast-transcription-create)
+> For fast transcription of audio files, consider using the [fast transcription API.](/azure/ai-services/speech-service/fast-transcription-create) Fast transcription API supports features such as language identification and diarization. 
 
 To instead transcribe audio files asynchronously, see [What is batch transcription](~/articles/ai-services/speech-service/batch-transcription.md). If you're not sure which speech to text solution is right for you, see [What is speech to text?](~/articles/ai-services/speech-service/speech-to-text.md)