I'm not so sure,Thompson .Mouth music as sang in English language Irish songs could in some instances have been attempts at imitating the old gaelic. The first Google search entry for the song Juice Of The Barley For Me gives the chorus as:
" Singing banya na mo if an ganna. And the juice of the barley for me."
That's the way I always used to sing it thinking it was just mouth music .
Check out the Buttermilk Hill chorus as sung by Peter Paul and Mary:
Shule, shule, shule-a-roo
Shule-a-rak-shak, shule-a-ba-ba-coo
See this link for how the original Gaelic chorus became "splendidly mangled" :
https://mainlynorfolk.info/folk/songs/shuleagra.html