"Píobaireachd takes the basic form of a rondo: a theme and variations with periodic return of the theme. It comprises:
—a 'ground' (or ùrlar, pron: oorlur, which provides the basic theme)
followed by variations of different sorts including perhaps:
—a 'thumb variation' (or siubhal ordaig, pron: shewell ordik) in which high A or high G is substituted for certain notes in the ground —various other kinds of siubhal which involve pairing themal notes from the ground with lower notes on the chanter such as A or G —a leumluath (pron: lemla) which combines the themal notes from the ground with a conventional gracenote figure revolving round a tonal centre on E —a taorluath (pron: toorla), which combines the themal notes from the ground with a different conventional gracenote combination centering on A —a crunluath (pron: croonla), which combines the themal notes from the ground with still different gracenote combinations.
There are other types of variation, but the above are the most common."
—William Donaldson, Pipers: A Guide to the Players and Music of the Highland Bagpipe (Edinburgh: Birlinn, 2005), 28
Some hints:
'urlar' is just Gaelic for 'floor'.
'siubhal' or 'siul' is a walk
'ordog' (probably 'ordag' in Scots Gaelic) is a thumb
So 'siubhal ordaig' just means "a walk for the thumb".
'luath' means 'early', but I don't recognize the various prefixes.
"Píobaireachd takes the basic form of a rondo: a theme and variations with periodic return of the theme. It comprises:
—a 'ground' (or ùrlar, pron: oorlur, which provides the basic theme)
followed by variations of different sorts including perhaps:
—a 'thumb variation' (or siubhal ordaig, pron: shewell ordik) in which high A or high G is substituted for certain notes in the ground
—various other kinds of siubhal which involve pairing themal notes from the ground with lower notes on the chanter such as A or G
—a leumluath (pron: lemla) which combines the themal notes from the ground with a conventional gracenote figure revolving round a tonal centre on E
—a taorluath (pron: toorla), which combines the themal notes from the ground with a different conventional gracenote combination centering on A
—a crunluath (pron: croonla), which combines the themal notes from the ground with still different gracenote combinations.
There are other types of variation, but the above are the most common."
—William Donaldson, Pipers: A Guide to the Players and Music of the Highland Bagpipe (Edinburgh: Birlinn, 2005), 28