In the islands off of Scotland where wool clothing was traditionally made for many centuries, the process of working the wool into an airtight weave was  a communal event, done by women.  When tweed is made, it needs to be fulled to increase its ability to keep out the wind. The word 'waulking' is a Scots word from the 14th century meaning the same as "full" in English. The waulking process not only fulls the tweed but also shrinks it slightly.
Waulking is a process of repeatedly beating the cloth to full it and prepare it for use.The process is called "orain luaidh" in Gaelic. The music associated with this labour contains vivid and intimate personal poetry, mostly the composition of women.   It is a system of rhythmic choral responses intertwined with Gaelic verses, pounded to the time of the wool being moved around the waulking board, where these women sat for hours working the tweed. 

Bannal is a group comprising many well known singers, they are:
Kenna Campbell, Catherine Fletcher, Christine Grant, Wilma Kennedy, Mairi MacArthur, Chrissie MacInnes, Maeve MacKinnon and Mary C MacLean.