ABSTRACT
This chapter discussses a diachronic perspective on language and focuses on the type of language change known as grammaticalisation. Grammaticalisation has received a great deal of attention within cognitive linguistics. This is because grammaticalisation is characterised by interwoven changes in the form and meaning of a given construction and can therefore be seen as a process that is essentially grounded in meaning. There are a number of different cognitive theories of grammaticalisation, each of which focuses on the semantic basis of the process. After providing an overview of the nature of grammaticalisation, it discusses three of these theories are metaphorical extension approaches; Invited Inferencing Theory; and Langacker's subjectification approach. The cyclic nature of grammaticalisation is evident in the fact that linguistic units enter a language as open-class lexical items, evolve into closed-class items via the process of grammaticalisation, eventually leave the language via a process of loss and are replaced by new open-class items.
