@Gregory Poleacov You can use Azure speech service for commercial purposes as long as you are paying for the service in your subscription. That is, you shouldn't be using a subscription with free azure credits for commercial purposes. If your subscription is a Pay-as-you-go type and you if you have created a speech resource with any pricing tier, then you can use the API for your personal and commercial purposes. However, please go through the Responsible AI guidelines for Azure to ensure that your application does not breach any of the guidelines or isn't misused by the users of your game.
If an answer is helpful, please click on or upvote
which might help other community members reading this thread.