Your company has thousands of recorded customer support calls in multiple languages stored as audio...

For thousands of recorded support calls stored as audio files in Azure Storage, the correct capability is speech to text batch transcription .

Microsoft states that batch transcription is designed to transcribe a large amount of audio data in storage , including audio files in Azure Blob Storage, and that files can be processed concurrently to reduce turnaround time.

Real-time transcription is for live audio, not large stored batches. Text to speech converts text into audio. Speech translation translates speech between languages, but the requirement is to generate transcripts.