To me, music is emotion put not in words, but expressive notes. It transends any and all languages because all who hear it, recognize it as music (whether they like it or not makes no difference in that point), and most will understand the emotion behind the highs, lows, slow, or fast tempo. As a musician, music is first math in whole & fractional numbers, requiring skill to play each note exactly in the time-frame the author intended, and secondly to bring the music alive by either adhering to or manipulating the tempo, based on the emotion I wish to convey (either the author's or mine). Math is also an international language.
The Celtic music I play is considered folk music. The instrument I play (bagpipes) is a folk instrument. There's modern Celt music, of course, so when you ask for a Celtic opinion, you're asking something that covers hundreds (if not thousands) of years. I currently play known common folk songs, but to me the most beautiful sound is the Piobaireachd (classical). But I digress. I've given my opinion on music itself, and perhaps if you consider it, it may help your paper in some small way.