Garena should look into players' preferred languages and group them into teams respectively.
It's extremely frustrating if you have someone who only speaks Viet and who replies you with cryptic messages.
League of Legends is a team-effort game. It's fine if your teammates don't understand you as long as they at least respond to your pings. Yet, what I see are Viet players speaking to one another in a language only they understand, and pushing, getting themselves pwned when the other team members ask them to get back. Garena's LoL is NOT a Vietnam server, players should speak with one another in a global language.
If the only language a person knows is his native tongue, then there should be a queue-matching feature which groups them with others who speak the same tongue.