What is the term for a variation of a language spoken by a particular group of people?

The term for a variation of a language spoken by a particular group of people is "dialect." A dialect encompasses differences in vocabulary, grammar, pronunciation, and usage within a specific language, often reflecting the cultural identity of its speakers. Dialects can be influenced by regional, social, and ethnic factors, leading to distinct forms that may be recognized as separate from the standard form of the language.

In contrast, an accent primarily refers to the pronunciation aspects of a dialect that distinguish how words are spoken, rather than the words or grammar themselves. Slang consists of informal or nonstandard words and phrases that often arise within specific social groups, but it is not characterized by the broader structural variations seen in dialects. An idiom is a fixed expression whose meaning cannot be deduced from the individual words, representing a unique cultural expression rather than a variation of a language. Thus, dialect is the most accurate term for a variation of a language among a particular group.