Tibetan greeting

Tibet in the 1930s: Theos Bernard's Legacy at UC Berkeley

Tibetan greeting

Sticking out one's tongue is a sign of respect or agreement and was often used as a greeting in traditional Tibetan culture. According to Tibetan folklore, a cruel ninth-century Tibetan king had a black tongue, so people stick out their tongues to show that they are not like him (and aren't his reincarnation).