First, navigate to "Language" settings
From an activity's overview page, open activity settings
Select "Language"
Enable speech-to-text
Select "Writing or speaking" or "Speaking only"
Select whichever fits best based on your preferences. "Speaking only will disable the ability for users to type responses in the chat box.
Enable text-to-speech
Select "Listening only" or "Reading and listening"
For "Reading and listening", you will have the option of choosing between having autoplay and not having autoplay. If autoplay is not enabled, users will need to click the "Listen" button to have the chat played back to them.
You have just enabled speech-to-text and text-to-speech for your activity! 🎉