Twilio fetches and
<Plays>s the MP3 for your caller. Pretty much any audio format works, MP3, Wav, AIFF... whatever ya got, just throw it at Twilio and we'll sort out the details
<Gather> keypad digits, and POST the result to your server, where your application decides what to do, and return a new XML instruction document.
Twilio
<Say>s your text to the caller, so you can build dynamic data driven voice apps.