What problem would you like to solve? Please describe:
The default Twilio Basic Man voice is not good, and sounds very robotic. Twilio supposed much better Text To Speech voice engines, such as Amazon Polly Neural. When using TTS engines, it is also best to set the language so the TTS engine will cover the local vocal nuances.

Describe the solution you'd like:
Add options to default the language to en-US, like it currently is, and set the default TTS voice to Polly Neural. It should also have the option to easily adjust it to something else.

Describe alternatives you've considered:
NA

Additional context:
NA