A rare but critical occurrence often occurring after a stroke or head injury, where a person looses their vowels, example: a,e,i,o,u and sometimes they loose y. Loosing a vowel creates a type of sound in pronunciation for which there is no closure of the throat or mouth at any point when vocalization occurs. Often a person who looses their vowels seem to be speaking a different language or tongues. A early example is in the biblical book of Acts. The apostles had come together in a barn to worship the Lord, and nobody understood what they were saying, probably because the Romans had beat them silly with sticks or something.
Steven was walking his ass and suddenly the ass kicked him in the head, when we found Steven I asked him wuz up.. He said gt kck n m hd b th ss. By inference I knew he meant " I got kicked in my head by the ass." It occured that he was suffering a concussion that gave him the lost vowel syndrome.