What is it called when a group of vocalists or chorus sing Ooh's oh's, ah's,
In my Gospel choir and school classes
I used the term "back ground"
back-ground voicing or back-ground singing
The typical arrangement of aah and oohs is that they are just homophone voicing the lead singer harmonizing the chords like an organ or guitar accompaniment.
(Of course will find also polyphonic background voicing.)
I've deleted the links provided as they haven't been corresponding to my text above. What I mean is not the same as backing voices or backup singers or also barbershop style.
I just taught the children to sing the chords (triads) following the tune in half notes or whole notes e.g. the background voices in Hey Jude.
Maybe the term "background" has changed its meaning through the years, but that's what we have used in Swiss Jazz School in the late sixties. And I would still use it in Jazz arrangements where instruments are playing divided chord notes like the Aah and Oh in harmony of human voices.
I thought that distinguished to consonants like mm, hm, nn, ng this kind of vocal accompaniment will be called vowel background.
But now here is the link with the correct answer:
BV's = BACKING VOCALS