Also in your preferences, you should make your hotkeys look like this to prevent the echo:
![Image](https://ohmyctf.com/settings.png)
To do that, add keys (the +add button below) and then assign z (down) to Mute Microphone and assign z(up) to toggle Microphone mute.
say ok and your echo should go away, when you hit the z key (or whatever key you use) you can chat in game without talking to the teamspeak server.