Songs in Scottish Gaelic can be arranged into two main categories - rhythmic songs, such as waulking songs and puirt-à-beul (mouth music), in which the tune is more important than the words; and songs in which the words are more important. The tunes of songs of the latter type can change from one verse to the next to fit the words.
Waulking songs are traditionally sung by women while waulking or fulling cloth, which involves a group of people beating newly woven tweed rhythmically against a table or similar surface to shrink it and make it water proof. Often one of the women would sing the verses and the others would sing the chorus, which is often made up of vocables (nonsense syllables).
Waulking songs were probably last used for waulking cloth in the 1950s. They are also sung in Nova Scotia by women and men, and are known as milling frolics.
This type of song is intended mainly for dancing to, and the rhythm is more important than the words. They are also a way to sing fiddle tunes, especially in Cape Breton, where knowing the words are an inseperable part of learning such tunes.
It's common to sing three or more of these songs in succession, sometimes getting faster and faster with each one.
Gaelic Song and Music
Traditional Gaelic song and singing sean-nós
Gaelic song archive on BBC Alba
Scottish folk songs
Courses in Scottish and Gaelic traditional music
Mary Ann Kennedy (Màiri Anna NicUalrig)