What is the cause for linguistic change?

All languages change over time, linguistic change can be seen in many areas of language eg in phonetic, morphological, semantic, syntactic features.

For example there are lexical changes due to the influx of new Words into a language. Changes in the phonetics of a language could be due to the popular culture of the time. Factors such as migration and movement bring about changes in a language. Geographical isolation can result in the formation of dialects or new languages.