Nation states as we know them today didn't exist in the 12th century obviously.
Ireland did however have a recognised High King at that time, Ruaidrí mac Tairrdelbach Ua Conchobair ( Ruairí Ó Conchúir in modern Irish, or Rory O Connor in English). The nature of the High Kingship was not like the traditional feudal idea of a King, the regional kings held most real power in their areas, and indeed local kings were often quite independent. Just like the role of the US President is nothing like the role of the French President today. That said O Connor was active on a national level in areas such as church reform and indeed developing infrastructure.
Ireland was an integrated cultural, social and legal entity. The written Irish language was standard throughout the country as was the Brehon legal system. This standardised spoken language was most unusual at the time. German, French, Italian were mostly spoken languages with little standardisation in their written forms. Latin was of course much more standardised but was not the spoken language.
The Brehon legal system was unique in that it was national law code administered by judges rather than the codification local customs with some remnants of the Justinian canon all enforced by the local political power.