Irish English (IrE) was initially learned as a second language as a result of the successive colonizations of Ireland by speakers of English and Scots dialects that began in the Middle Ages and reached a peak during what is termed ‘The Plantation Period’ of Irish history. The scheme persuaded English and Scottish settlers to colonize the island of Ireland, hailing from urban centres like London as well as more rural areas like Norfolk and Galloway. This intensive colonization process created the possibility that a novel type of English could emerge. This new variety is characterized by: (i) innovative forms; (ii) the incorporation of features drawn from Irish, the indigenous language prior to colonization, and (iii) other characteristics caused by the mixing of Irish with the regional Scots and English vernaculars of the new settlers. Interestingly (and not uncommonly when migratory movements of these kinds arise), modern varieties of IrE still retain this mixed heritage. Moreover, the colonization is preserved culturally – particularly in the north of Ireland – by ethnic divisions between the descendants of the migrant and indigenous populations. Thus, Catholics, who reflect the latter group, celebrate events like ‘St Patrick's Day’ while their Protestant neighbours commemorate ‘The Glorious Twelfth’ each July, celebrating the day in 1690 when King William III's victory at the Battle of the Boyne ensured the ultimate success of the Plantation scheme in which their forefathers participated. The linguistic consequences of this contact permeate all aspects of the speech used within these communities (accent, grammar and vocabulary). Moreover, some of the grammatical features that are the focus of this article have travelled to regions that have been intensively settled by Irish migrants. Hence, these features also have important implications for the study of transported dialects, which has recently become very topical and is the focus of a new strand of research in English variation studies typified by the publication of Hickey (ed. 2004).