gadhelic

from The Century Dictionary.

• Of or pertaining to that branch of the Celtic race which comprises the Erse of Ireland, the Gaels of Scotland, and the Manx of the Isle of Man, as distinguished from the Cymric branch. See Cymry.
• noun The language of the Gadhelic branch of the Celtic race, comprising the Erse, Gaelic, and Manx.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Of, belonging to, or designating, that division of the Celtic languages which includes the Irish, Gaelic, and Manx.