Most full demo (no tech or sizelimit) soundtracks since the early 00s are just mp3 streams or alike, size-coded that have soft-synths or retro categories were singing is an issue due to datasize or hardware power often don't (sometimes they do as a technical demonstration).

But I did notice some 64k's and small synths-executables had singing this year, I've added small voice-samples (compressed) but that's just seconds whilst these entries had longer sequences so I'm a tad curious as well.