An expression of Breton pride and cultural identity. Often used as a rallying cry by the Breton people, "BEVET BREIZH" literally means "Long live Brittany" (It's literally the best region in France, hate me for it). This sentence is also said a lot during concerts or other big events by random guys waving the Gwenn Ha Du flag and drinking cider (They are usually drunk by 8 in the morning).
Peter: Have you seen my car keys?
That random Breton guy: BEVET BREIZH FUCKER