This is the real exciting part. When your application responds to Twilio with XML, we treat it like a set of actions to perform. Verbs! Here's what you need to know:
<Response><Response> (not <response>)<!-- COMMENTS HERE -->Here are the core five Twilio Verbs...
<Say>: Say some text to the caller<Play>: Play an audio file to the caller<Gather>: Gather phone keypad digits and submit them back to my application<Dial>: Dial another phone number and connect the current call if someone picks up<Record>: Record the caller's voice and submit the recording back to my application