Irish is only a symbolic language on Ireland. I doubt that it is the mother tongue of anyone these days. If it is, then the person is fully bilingual with English as their second mother tongue, spoken with no accent other than the normal accent that Irish people have when they speak English. I think. I am almost sure that has been the case for 100 year.
There are about 100 000 native Irish speakers now, there were more a century ago, some of them were monoglots.