I' ve looked it up on the Internet.
イラヨーヘイ イラヨーホイ ヘイヨー ヘイヨー
…囃子言葉 Hayashikotoba (a meaningless refrain used to maintain the rhythm of a song.
It might have had meanig in old ages, but now it's unknown.)
ゆういりよーや
…芯のある強い子になれ (Grow up into steady person)
This song is in Okinawa dialect, which is difficult to make it out even for many japanese.
I didn't know this song but it's so good! Thank you for telling.