This document discusses the types and mechanisms of language change. There are three main types of language change: lexical, grammatical, and sound level. Lexical change involves changes in word meanings, such as semantic extensions or reductions. Grammatical change includes morphological changes that alter word forms and syntactic changes that modify word order patterns. Sound change affects pronunciation and can involve processes like assimilation, dissimilation, deletion, and diphthongization. Language change occurs across all levels of language over long periods of time as a result of both internal and external influences.