STARK is an application that allows you to use Text-to-Speech and play back audio through your mic in Source engine games using in-game chat commands.
This project has evolved from a proof of concept that I made a long time ago in a galaxy far, far away using AutoHotkey link
There's a high likelyhood you'll fail (not your fault, the current release is very, very buggy)
However, if you want to try anyway, here's a tutorial:
Here, there be dragons
If you want to contribute to this project, don't. The code is being rewritten for v2 and is not ready for public use. So if you really want to contribute, wait until the v2 release.