One of the functions of Apple Music is to show the lyrics of its songs, so you can read them as the song plays and learn them or even sing them if you feel like it. But of course, there are instrumental songs in which absolutely no one sings. Doesn’t seem to be a problem for Apple Music
“Duh-duh-duh-duh”
This is evidenced by this screenshot you can see below, in which Apple Music plays the Star Wars opening theme composed by John Williams. A mythical tune that everyone hums but has no lyrics, so… the service does not hesitate either to hum:
The phrase “a long time ago in a galaxy far, far away” it doesn’t appear in the song, but Apple places it in the lyrics to just mimic the moment before the melody sounds in all nine films in the saga. Someone on the Apple Music team must be very, very passionate.
‘Duh duh duh duh duh’ is very open to interpretation, but no one can claim that it works. And beware, I tried to see if Spotify has the same lyrics and it doesn’t. Point to Apple for originality. Either the obvious or cartbut you prefer to evaluate it.