Colloquialisms are words and expressions that become commonplace within a specific language, geographic region, or historical era. Authors use colloquialisms to give personality and authenticity to their characters.

Why would an author use colloquialism?

Colloquialism is the use of informal words or phrases in writing or speech. ... Writers often use colloquialism in dialogue or first-person narration, both because it helps make their characters seem more lifelike and because the way a character speaks may be one of their defining qualities.

Why is colloquial language effective?

Colloquial language is used in informal writing situations and creates a conversational tone. Everyday spoken language gives your writing a casual, relaxed effect. Colloquial language is not necessarily “wrong,” but it is used when a writer is trying to achieve informality.