[2020] Thread about a matchmaking patent filed by Activision Blizzard

overwatch does not use any analysis of chat (voice or text) for matchmaking.

without going overly into details, overwatch match makes on:

--your matchmaking rating (MMR) - this is mostly affected by win/loss, with variance applied for certain conditions (i.e. brand new player, among other things)

--your region

--your ping

again, that's overly simplified. but that's basically it.