Informal language is the language that is commonly used in everyday communication with friends, family, or colleagues. However, there are several synonyms for informal language that can be used depending on the context. Slang is one such synonym which is a type of informal language that is specific to a particular group of people or culture. Colloquial language is another synonym that is informal but still acceptable in formal settings. Vernacular, jargon, and casual language are other synonyms that can be used interchangeably with informal language. While each of these synonyms has its own nuances, they all relate to language that is relaxed, easy-going, and casual.