Peg (and Sile) "Good on ye" and good luck to you and your groups. Nothing can touch the soul like good a capella singing, especially the choral variety. Being neither a "trained" musicologist nor linguist, I don't know how to distinguish between a capella singing in accord with musical conventions from the renaissance era and "sean nos" singing, which I assume stylistically pre-dates the renaissance by a significant span. Part of the difference is likely in "non-standard" tuning and in the variance of vocal intervals within an octave. Not being a Gaelic speaker, I hear Gaelic singing differently than a speaker would, and thus respond to it differently. The voice(s) is/are the equivalent of instruments, and I can respond to the emotive pulls of the sounds rather than to the message of the words. I'm not sure if I'm explaining that in a sensible fashion. Hope so. Moreover, Gaelic seems (at least to my ear) better suited to the sean nos style than English. I have the sense that the sounds in Gaelic can almost be "swallowed" by a sean nos singer. Perhaps it's that they are created further back in the throat or some such, but either way, the sensation adds to the enjoyment for me as a listener.