Subha’s name means “sweetly speaking.” The literary device that her name ilustrates is IRONY due to the fact that the girl cannot speak.
The literary device irony is defined as a literary technique, originally used in Greek tragedy, by which the full significance of a character's words or actions is clear to the audience or reader although unknown to the character. Irony involves the employment of a language that normally signifies the opposite, typically for humorous or emphatic effect.