There are many ways to use linguistics every day. Some linguists are theoretical linguists and study the theory and ideas behind language, such as historical linguistics (the study of the history of language, and how it has changed), or the study of how different groups of people may use language differently (sociolinguistics). Some linguists are applied linguists and use linguistics to do things. For example, forensic linguistics is used in crime investigations, and computational linguistics is used to help make computers understand languages, as in speech recognition). 