Party chats of some sort while in the middle of a game?

Is there any ways to only chat to people you partied with? Me and my friend play a lot of league together, and he has a mic and speaks to me on discord. I don't have a mic though, and I'm forced to type back. I really don't feel like typing to my entire team to talk back to him, mainly because it may irritate my team from all my typing and it'll seem like I'm talking to myself or something. So just would like to know if there is any kind of party chat integrated in league or maybe some external program may put it in league.