Language & rhythm: Kikongo, Franco’s mother tongue. Decca (bass) and Dessoin (percussion) had the same background and play here, Decca even animates (from 7:08 into the song).Kimpa Kisangameni (Franco) - Franco & le T.P. O.K. Jazz 1983 (1 download)
Other vocalists, besides Franco: Josky Kiambukuta and Aimé Kiwakana, possibly Chécain, who might also be responsible for some light percussion, too. Dele Pedro and Rondot Kasongo Wa Kasongo may have played soprano saxes (during the intro only). Ntesa Dalienst explains after the song. Ntesa went on (but I could not fit that into the maximum 10″59 minutes for YT) to say that Franco believed that indeed sorcery was the cause of his illness, which he had said in an interview very near his passing. Franco’s guitar is crying all through the song, deep in the mix. If you play it loud, you may catch it.