wouldn't it be cool if you could "understand" the language of your faction?

Like when you play as a samurai, all the voice lines from other samurai characters in the game would be english (Or whatever language you selected) as it would be your native language?

take the knight heroes as an example:
When you play as a viking or samurai, you will hear: "Incredibilis!" / "Ad mortem inimicus!"
When you play as a knight, you hear the following: "I'm incredible!" / "Death to the enemy!"

You get the point

This could be turned off, as your own lines would always be in english by that logic.