The Evening Bell (1970)

Name: The Evening Bell
Director: Shin Sang-ok
Released: 1970
Cast: Choi Eun-hie, Jin Kyu Kim

IMDb

The son of a mute couple succeeds in getting a good job, but is dismayed when he learns that he may have gotten the job, not based on his business skill, but on his ability to speak sign language. This rumor comes about because the boss has a deaf daughter whom he wants to marry off as soon as possible.