Doesn't this sound an awful lot like Duo Queue?
Riot Lyte
We also saw that teams with mixed communication (some in voice, some in text) were more toxic... and it was interesting because the toxicity was from the players in voice chat. What was weird was that the players in voice chat were up to 126% more toxic in text chat to the players who were not in voice chat! The players in voice chat also received 50% more reports, even though in many cases the other players were not aware these players were in voice chat.
This was in response to a question about adding voice chat in LoL (http://ask.fm/RiotLyte ). Mixed communication already exists in the form of duo queue, where premades usually chat on teamspeak with eachother. What do you think of this?