Asklemmy

This question has some weird conditions on it - "doesn't repeat itself" is the most troubling one. Pi has an infinite number of sevens in it (so it repeats the same values quite often) but it's unique in its entirety - it also has infinitely long blocks that are repeated because, you know, infinity be weird like that.

I'd point you to a symphony like Vivaldi's Seasons or, if you're willing to substitute "words I can't understand" for "words" (and don't happen to speak German) Der Ring des Nibelungen. While the later does have talkie bits understanding those gives you barely any more context than the raw emotion of the music.

But, both of those (and all music that doesn't suck) relies heavily on repetition... but they're also unique overall (unless they don't have a strictly defined form aka jazz but now we're really in the weeds)