A recent Q&A by Riot Games in Korea (as translated by Reddit user Calycae) has revealed some interesting news regarding voice chat in the game, and it may be coming to the game after all.
"As you've said, League of Legends is a team oriented game so communication is important, and games are played strategically. Because of that, In-game voice chat is currently being interally reviewed," Riot said. "Previously we worried that voice chat would lead to toxic behaviors, but after rethinking, we ultimately decided to provide an in-game voice chat feature."
"League of Legends promotes team-sport oriented teamwork, and we think that voice chat brings value to when players are matched with random players, so we are reviewing the feature at the moment. After the game client update has been applied, we expect concrete plans and preparations to be possible. It is difficult to say exactly when, but we would like to let you know that we are working progressively on bringing this feature ready and working."
Another post by Riot's Community Manager clarified this a little though, saying: "Voice chat is being internally reviewed very positively, however it is not something that has been confirmed. If we were to bring this feature to live servers, we will try our best to reflect upon the player's worries and requests."
It seems to be important to Riot, then, to emphasise that voice chat isn't definitely coming, but it's looking positive. Would you like to see it introduced into the game?