I'm from Northern Ireland myself and when I've went abroad with people from between 30-60 miles away from me foreigners mocked us for having such different accents and often using different words, claiming we obviously live in medieval times and can't travel between towns so I've seen how it happens here with so many rural communities but I still find it amazing that the "same word" ends up sounding like completely different words! Standard Irish is difficult enough as it is without learning all the dialects haha
The Irish for "suit" is culaith, and there are a number of different grammatical circumstances that trigger "lenition".
When culaith is used in a grammatical context that calls for "lenition", the lenited form is chulaith. When the grammatical context calls for "eclipsis", the eclipsed form is gculaith.
culaith - "a suit"
an chulaith - "the suit" (culaith is feminine, so an causes lenition")
mo chulaith - "my suit" (mo causes lenition)
ár gculaith - "our suit" (ár causes eclipsis)
It's culaith when there's no an (=the) before it. Culaith is a feminine word so that's why it changes with an/the. Of course, it would also be chulaith in other situations too! Eg. sa chulaith (=in the suit); do chulaith (=your suit) because sa and do force that change (séimhiú) on a word... Hope that helps - even though this was probably a long time ago! :-(