I agree with an earlier post from Sean Mac Ruaraiah, stating these choruses formerly had meaning, even if they have lost them of late.
I would point anyone interested in the direction of "The Druid Source Book" ISBN 1 86019 8422 and particular to the chapter by Charles Mackay,
on "Druidical Chants Preserved In The Popular Songs Of England, Scotland,Ireland and France.
It is eye-opening! I did not fully believe it all, untill I had it examined by an old Gaelic fluent friend Dicky Lett, of the sainted memory! who to my amazement confirmed all the chapter contains.
I sugest any doubters do the same, and examine this text.
Sorry I am technically incapable of helping you further.
Good Luck, Scowie.