The unstressed ending -eo produces a sound that can oscillate, depending on the case, between [ɔw] ~ [ju] ~ [ew]. For consistency we retain it, as many authors do, for words that originally had it and still form their plural in -ei. From angeo [ˈaŋdʒɔw] “angel” one will have angei [ˈaŋdʒej], from umeo [ˈymˑju] “humid” and “humble” one will have umei [ˈymˑej] ~ [ˈymˑi], etc.