This article examines the implications of the mediatisation of Irish English vernacular forms in radio advertising in Ireland, through an analysis of a corpus of 160 radio advertisements, broadcast in the years 1977, 1987, 1997 and 2007 on a prominent Irish radio station. It investigates how vernacularisation as social change is manifested in this context, and how this process impacts the status of vernacular Irish English varieties. This study examines whether the media representation of vernaculars in the Irish radio broadcasts facilitates metalinguistic reflexivity and valorises vernacular forms, and also discusses the use of such strategies as 'dialect stylisation' in representing 'authentic' language in such contexts.