Help with playing audio clips in games

[3020]

Hey everyone, I was wondering if someone knew how to play audio files in online games instead of talking with a mic. I also need it to not interrupt the game and make me tab out every time. I don't have a mic right now and really need to communicate with team members since I'm playing left 4 dead and I find that teams with better communication are more fun to play with. Thank you in advance to anyone who can help me.