The Japanese word for tongue is
舌

した - shita

tongue

Japanese Definition

tongue
1. 名詞. 舌した
2. 名詞. 言語　（類義語language, lingo）
He was speaking in his native tongue.
3. 動詞. （音楽）タンギングする。管楽器を吹く時に、舌の運動によって空気の流れを断続させる。(alveolar plosive).

舌
1. n. tongue

べろ
1. n. (anatomy colloquial) the tongue
2. n. (by extension) an object shaped like a tongue
3. n. (by extension historical, colloquial) (synonym of ja, 小判, tr=koban): a small oval gold coin with a face value of one ll, ja, 両, ryō
4. n. (regional colloquial) a cow