갤마다

Not very clear.

The general shape of the word corresponds to 갤차다 (gaelchada, “to teach”), a common Gyeongsang form of Standard Korean 가르치다 (gareuchida, “to teach”). But since /-m-/ clearly cannot correspond to /-t͡ɕ-/, it is more likely that an etymologically separate verb was partly merged with 갤차다 (gaelchada) due to semantic overlap.

갤마다 • (gaelmada) (infinitive 갤마)

1. (southeastern Gyeongsang) Only used in 갤마주다 (gaelmajuda, “to teach (something) to”).