This period stretches from the arrival of the Normans to the end of an independent Gaelic society at the beginning of the 17th century as a consequence of English military successes and increasing anglicisation of Ireland. The old form of Irish society in which poets still had a place, however tenuous, came to an end so that there was no continuation of a single written standard. Indeed it is unlikely that such a standard would have survived as it was long since remote from spoken forms of the language. The anglicisation accelerated a process which had begun long before, it did not initiate it.

It is in this period that a series of instructions for poets were composed intending to act as guidelines for those wishing to use the classical standard for poetic composition at a time when the latter was no longer spoken anywhere. These are collectively known as the Bardic Syntactical Tracts (McKenna 1979 [1944]) or as Irish Grammatical Tracts (Bergin 1915-25) and date back to the late 15th century or perhaps earlier (Ó Cuív 1965: 142).

The early modern period is characterised by the language of a professional class of poets called filí. The period itself is known as aos dána ‘the age of poetry’ and is referred to in linguistics as Classical Modern Irish (McManus 1994). The writers of the period were mostly secular employees of Irish courts (witness the quantity of praise-poetry produced, Ó Cuív 1965: 143). They clung to obsolete norms but were not completely conversant with the older forms of Irish which they emulated and the result was language hampered by its own artificiality. In this period the dichotomy of the older norm and contemporary usage lead to a tension between what was called ceart na bhfileadh ‘the poets’ standard’ and canamhain ‘speech’, i.e. the spoken Irish of the time.

Linguistically, the Early Modern Irish period is a time when the changes initiated and partially carried through in the Old and Middle Irish period were consolidated (McManus 1994). The verb prefixes are reduced in number, e.g. do-, ad-, no- and ro- frequently level to do- which is still present as a marker of the past under certain circumstances. Independent personal pronouns became normal with a single form of the copula verb. Indeed this pattern – invariant verb form and independent personal pronoun – spread to other verbs and has become common in Modern Irish outside of the present tense which does, however, retain synthetic forms.

As with Middle Irish, there is no contemporary handbook of Early Modern Irish, although there is an older work by Georges Dottin from 1913 (second image below). The best treatment of this stage of the language is probably the following long article in Stair na Gaeilge :

McManus, Damian 1994. ‘An Nua-Ghaeilge Chlasaiceach’ [Classical Modern Irish], in: McCone, Kim, Damian McManus, Cathal Ó Háinle, Nicholas Williams and Liam Breatnach (eds) 1994. Stair na Gaeilge. In Ómós de Pádraig Ó Fiannachta [The History of Irish. In Honour of Pádraig Ó Fiannachta]. Maynooth: Department of Irish, pp. 335-446.