Historically, the traditional music of Ireland and Scotland, not identical but related, in its pure form consisted of solo voice or a single instrument such as pipe or fiddle. As a revival sound it's come a long way from such austere origins. It reached its commercial peak during the "Celtic music" fad of a few decades ago. (The phrase "Celtic music" was always a marketing category, not a description of something extant in nature. In fact, there is no animal as pan-Celtic music. In recent years, moreover, ethnographers have begun to doubt that the Irish and the Scottish are "Celtic" peoples in any meaningful sense.) The Pennsylvania-based Runa continues the urban modernization of rural music on The Errant Night (a play on the ballad title "The Errant Knight") on this, their 10th album.

Which is a splendid one indeed. The musicianship is of a high order, and happily applied to a generous 15 cuts and nearly an hour and 10 minutes' worth of creative arrangements of mostly trad material -- fiddle tunes, ballads and shanties, along with a Karine Polwart song and two by David Francey, plus a vintage pop tune and a "John Riley" that is not the one you think it is. The five members of the current Runa lineup perform with a range of majorly talented guest artists.

If not traditional in its approach, which borrows from jazz, rock and bluegrass when the occasion fits, Runa is certainly traditional in its spirit. I have heard just about every older song and tune on Errant performed in its more standard style, but the band dresses each up in a setting that affords the material new resonance. The shantey "Again for Greenland," which opens the disc, first seemed to my ears something I'd never heard before until I at last recognized the lyrics. Here as elsewhere the band comes across nearly as radical as the late, lamented English folk band Bellowhead. If we are lucky, Runa will not be similarly late and lamented anytime soon.

Years ago, in London, I met a man from Glasgow and fell into conversation with him, during which we discovered a mutual passion for the late Canadian novelist W.P. Kinsella, whose most famous work is Shoeless Joe, on which the popular film Field of Dreams was based. (The novel is better.) I know of the folk song "Glasgow Peggy." I have been informed that Glasgow, or some of it, is rough and scary. I have now exhausted my knowledge of that city.

Unfortunately, I am unlikely to learn more from Mary Ann Kennedy's tribute. Glaschu is Gaelic for Glasgow, and the album is sung in that language. (Some of the spoken recitation is in English.) By now, after a long listening life, I know how to hear recordings in languages I don't speak: focus on the sounds of the words as they link with the melodies, and you sort of get the idea. I have even been driven to tears by songs of whose lyrics I didn't understand a word.

Kennedy, not new to me but not wildly known either, has a dark voice, resounding yet intimate, which does not let a listener's attention stray too far. Not that one would want it to. Some melodies I recognize as older than the lyrics, which I infer are mostly contemporary. So is the occasional tune, representing the increasingly multicultural city. "Mother Glasgow" can best be characterized as a Gaelic saloon (as opposed to pub) song.

If Kennedy sometimes defies expectations, I am reflexively drawn to the more familiar, which means the trad or trad-based. I am not especially proud of that, though there is (happily from my no doubt narrow point of view) plenty of it here. I am also aware that Glaswegians don't wander their streets singing songs from a century and more ago. I further acknowledge that Kennedy is in full command of any song, whatever its style or root, that she chooses to do. The spare and evocative production proves keenly effective in shaping the cold loveliness that is Glaschu. I can't speak to Glasgow.