Initially proposed (as xe'e) by John Clifford (as an interpretation of Jorge Llambias' xe'e (xe'e1): renamed by Jorge Llambias to xa'a. And Rosta then suggested xa'anai take over from (his own) xo'o: renamed by And Rosta to xo'u to avoid clash with Gerald Koenig's xa'a: threads on mailing list archives involving this cmavo:
I have no idea how people at the time kept track of all this. --nitcion
--I'm not sure we did. --And.
It should be noted that the discussions involving these cmavo to indicate scope-leaping (and non-scope-leaping) ended with the fatigued conclusion that afterthought scope indicators -- which is what xo'u was -- would be just too complex and hasslesome. Scope must be done in forethought by means of prenexes and left-to-right order within bridi. --And.