Not really   they are sninigg an English version of a piece that originally had a German text. As well as existing in other languages, Jesu is actually a word in the English language, pronounced with a Jee sound.It would make sense to pronounce it Yay if you were sninigg a Latin, for example, but it seems strange to pick one word and sing it in a different language, unrelated to the work you are sninigg.