Irish twins

"Irish twins" isn't a phrase that's from Ireland, it's an offesive phrase used outside Ireland, so there's no equivalent Irish translation.

"twins" is "cúpla"

Irish twins is a name given to a set of children in the same family who are born 13 months apart.

There is no proper term for "Irish Twins" (a derogatory phrase by the way). They would simply be siblings.

No, twins are born within minutes of each other, not years. Irish twins are a year or less apart in age. Aggie80