Japanese edit

For pronunciation and definitions of なまる – see the following entries.
鈍る
[verb] become blunt
[verb] decline in ability or energy, lose one's edge
[verb] lose skill, decline in competence, get rusty
訛る
[verb] to speak with an accent; to have a dialectal or foreign accent
(This term, なまる, is the hiragana spelling of the above terms.)