Look, I know communication is important but I also know if all players know their role, a simple ping usually will do the job.  If the player don't know what to do you hardly will be able to explain your plan in a timely fashion, although I admit, it's possible.

Of course, communication helps, specially to avoid stuff like duplicate items and who should go first / when to retreat, but again, it's learning a couple of words not getting a major in english.

Sometimes I feel people want to communicate either to demand something (lane, ward, courier, ganks) or to insult the other player. On my 1000+ games of DOTA I've seen very little "communication" outside "mid, please" and "buy wards" and the rest was just smack talk between angry players.