There are only a few remnants of the Gaelic Irish language in modern Irish English. 800 years* of oppression, y' know y'rself....
Go raibh míle maith agat in generous translation...
Bog The "jacks," the loo, the restroom.
Bóithrín Small roadway. Diminutive of Bóthar (road.)
Craic (pronounced "crack," and often spelled so) Good times; general goings-on, or social atmosphere [as in, "great craic," "what's the craic?" or "how's the craic?"]
Crúibín (pronounced "crew bean") Pig's foot. The term "crew beans" might sound like a euphemism, but it's not.
Fáilte Welcome. Used in tourism and on doormats.
Gaeltacht a political-science delineation of areas in which Irish is an important language in daily life. "The Gaeltacht" refers to the Gaelic-speaking whole although its components are divided into small enclaves, mostly in the west.
Guards The police.
Omadhaun (n.) Fool. (Rare usage)
Póg mo thóin Kiss my ass.
Poitín A beverage distilled from one of several accepted ingredients.
Shillelagh Traditional walking stick. Normal use of the term involves sale to naïve American tourists.
Sláinte "Cheers" (over a drink.) Literally, "health."
Sliotar (pronounced "slitter") The small hard ball used in the Gaelic sport hurling and the women's equivalent, camogie.
Tuig (pronounced "twig") To grasp, to comprehend.
The phrase "800 years of oppression" is common amongst the Irish, and refers of course to the long domination of the island by the British. Its accuracy is best debated by professional historians.
The Anglo-Normans landed in the southeast in 1169. They never dominated, nor have proceeding incursions.