Hi @athody ,
Yes, you can use and distribute the audio files and text generated from text-to-speech or speech-to-text for commercial or personal use. You just need to make sure that you are using a speech resource that is billed for your subscription. The billing will be based on the pricing listed in the pricing page. If you are using a free account or credit you should upgrade to Pay as you go.
You do not need to request permissions or licenses, or pay loyalty to Microsoft for using the output files generated from your resource as long as you are using your own content as input to the service. Please ensure to follow the responsible deployment guidelines listed here while using synthetic voices in your applications and ensure that you have included proper disclosures.
You can look up more details about the compliance and privacy terms from here. If you have more specific billing and licensing questions, I would recommend speaking with your licensing representative of choice or creating a ticket with the billing team.
Reference: Azure Speech to Text Commercial Usage