British, American and Irish English are all correct. Irish English uses British spelling, pronounces the r like American English and has plenty of words of its own.
Same thing, three names
Many everyday things have a different name in each variety.
UK trainers · US sneakers · IE runners
UK cupboard · US cabinet · IE press
UK mum · US mom · IE mam
UK police officer · US cop · IE garda (plural: gardaí)
Careful with chips: it means two different things.
UK and Ireland: crisps (in a bag), chips (hot) · US: chips (in a bag), fries (hot)
Same meaning, different patterns
Irish English has some patterns of its own. I’m after eating means I have just eaten; it is spoken and informal.
UK I’ve just eaten. · US I just ate. · IE I’m after eating.
UK Shall I open it? · US Should I open it? · IE Will I open it?
UK you lot · US you guys · IE ye
One word, three accents
Most Irish and American speakers pronounce the r in car and park; many speakers in England do not.
car: UK kah · US kar · IE kar
schedule: UK SHED-yool · US SKED-jool · IE SHED-yool
the letter z: UK zed · US zee · IE zed
Everyday talk in Ireland
Phrases you will hear every day in Dublin:
I’m grand, thanks. · Thanks a million! · What’s the craic?
It’s lashing. · He’s gas. · My mam was giving out to me. · Pass me that yoke.
Spelling
Ireland follows British spelling (first form); American spelling is second.
colour · color centre · center travelled · traveled programme · program