This is beautiful and brilliantly played. The lady fiddler is Aoife NicCormaic. She has a new album out entitled "Cuas na bhFainleog (The Hollow of the Swallows)." It is also very good but the band on the album are not quite as special as the band in this video filmed in 2009.
I have no idea how you pronounce "Aoife." Working on the basis that "Niamh" is pronounced "Neeve" my guess is that it is probably something like "Ruth." I am sure far more people would dare to learn Gaelic if somebody had the common sense to phoneticise the language. I mean, why use the Latin alphabet if you are not going to pay any attention to the sounds of that alphabet. It's just being separatist for the sake of it. I expect that off the Welsh but not the Scots or Irish.