Not to be causes of language change pdf with language shift. For errors in grammar, see Solecism.
Language change is variation over time in a language’s phonological, morphological, semantic, syntactic, and other features. It is studied by historical linguistics and evolutionary linguistics. Some commentators use the label corruption to suggest that language change constitutes a degradation in the quality of a language, especially when the change originates from human error or prescriptively discouraged usage. Descriptive linguistics typically does not support this concept, since from a scientific point of view such changes are neither good nor bad.
Economy: Speakers tend to make their utterances as efficient and effective as possible to reach communicative goals. Purposeful speaking therefore involves a trade-off of costs and benefits. The principle of least effort tends to result in phonetic reduction of speech forms.
See vowel reduction, cluster reduction, lenition, and elision. Analogy: reducing word forms by likening different forms of the word to the root. Language contact: borrowing of words and constructions from other languages. Geographic separation: when people move away from each other, their language will diverge, at least for the vocabulary, due to different experiences.