First, check out my guide on the Autoexec


If you want your V key to be push-to-talk (default) while also lowering game volume while you speak, use this script:

//Mic and Speakers Configuration
alias "defvolume" "volume 1"
alias "recvolume" "volume 0.05"
bind v "+newvoice"
alias "+newvoice" "+voicerecord; recvolume"
alias "-newvoice" "-voicerecord; defvolume"
echo MIC AND SPEAKERS CONFIGURATION ENABLED
//

If you want your V Key to be toggleable (On/Off) while also lowering game volume while you speak, use this script:

//Toggleable Mic without echo
alias "defvolume" "volume 1"
alias "recvolume" "volume 0.05"
bind v "voicetoggle"
alias voicetoggle "micspamon"
alias micspamon "alias voicetoggle micspamoff; +voicerecord; recvolume"
alias micspamoff "alias voicetoggle micspamon; -voicerecord; defvolume"
echo TOGGLEABLE MIC AND SPEAKERS CONFIGURATION ENABLED
//

NOTES:

• You can change the "v" to any other key
  
• You can change the volume numbers to anything you want from 0-1; "defvolume" will be the default volume and "recvolume" will be the reduced volume when speaking
  
• Anything behind two slashes "//" in a script will be ignored; these are labels
  
• Your console will read out the words after "echo" so you know it worked
  
• Everything in your Autoexec.cfg will load automatically when starting the game. To update changes made in-game, go in console (~) and type "exec Autoexec.cfg"

This is a fantastic resource for learning how to script