Why do Americans call the music from Scotland and Ireland Celtic music when it has nothing to do with the Celtic languages at all?

Americans (and others) call music from Scotland and Ireland "Celtic music" not because it’s directly tied to the Celtic languages in a linguistic sense, but because it’s rooted in the cultural and historical traditions of the Celtic peoples—tribes and societies identified by archaeologists, historians, and later romanticized in popular culture. The term "Celtic" originally comes from the Greek "Keltoi," used to describe a broad group of Iron Age tribes across Europe, including those in what’s now Scotland, Ireland, Wales, Cornwall, Brittany, and the Isle of Man. These groups shared artistic styles, like intricate knotwork, and certain social structures, though their languages and music evolved differently over time.

The music itself—think fiddles, bagpipes, harps, and lively reels or haunting ballads—developed in regions where Celtic languages like Scottish Gaelic, Irish Gaelic, or Welsh were historically spoken. Even if the lyrics aren’t always in those languages today (many songs are in English or are instrumental), the melodies, rhythms, and instruments trace back to those older traditions. By the 19th and 20th centuries, Irish and Scottish immigrants brought this music to America, where it got lumped under the "Celtic" label as a catchy, broad identifier for anything evoking that misty, ancient vibe—especially during the folk revival of the 1960s and ‘70s.

You’re right to question the language link, though. The Celtic languages (Goidelic branch: Irish, Scottish Gaelic, Manx; Brythonic branch: Welsh, Breton, Cornish) aren’t a prerequisite for the music. Plenty of "Celtic" tunes have no words at all or use English, especially in modern renditions. The term’s more about a shared cultural heritage—real or imagined—than a strict linguistic tie. Critics might argue it’s a bit of a marketing gimmick, too, lumping distinct regional styles (Scottish reels vs. Irish jigs) into one exotic-sounding category for American audiences. Still, the name stuck, even if it’s a loose fit.