Language variation is a field of study in linguistics that focuses on the differences and changes in language that occur between different groups of speakers. This can include variations in vocabulary, grammar, pronunciation, and other linguistic features that can be influenced by factors such as region, social class, age, ethnicity, and gender. Researchers in this area often study how and why these variations occur, as well as their implications for communication and language development. Language variation can also provide insights into the history and evolution of languages.