Colloquialization refers to the process of adapting speech-like properties in the domains of written language. The evidence of written language becoming more as spoken language is an increasing frequency of phenomena associated with spoken language and a decreasing frequency of phenomena associated with written language (Leech 2002). In my book I show the presence and progress of colloquialization in ICE- corpora of Ireland, Canada, Great Britain, Singapore, Jamaica and India by using the frequency of phrasal verbs as a measure of colloquialization. The evidence of colloquialization is provided when formal text material of spoken and/or written production or both show a high number of phrasal verbs. The examination of colloquialization in my research illustrated that stylistic change is present in all corpora under investigation but is different in terms of its spread. Decolloquialization, as the other phenomenon which may explain the observed change, is introduced and discussed on the results of analysis carried out in ICE-India.