Rechoice????

My darling little boy was singing a song yesterday and i was trying to decipher just which christmas carol he was so intent on singing. This is what I heard:

"Rechoice! Rechoice!
O he mad at me Rechoice!"

I can only assume the sweet innocent Garrett was trying to sing:

"Rejoice! Rejoice! Emanuel!" I've never laughed so hard! So I try to teach him the correct version and well it still comes out Rechoice!