I wrote: > It occurs to me that in a language >> with contrastive initial /?/::/0/, it might be the onset of >> /0/-initial >> words?? Since IIRC you're familiar with both Arabic and Hawaiian, am >> I > more >> or less right? From the various replies, it sounds like I was wrong. and: <Is there any friction, or is it smooth?> Again, evidently there is friction. So much for that idea.... I was aware of the Tongan situation, cited by Philip Newton-- there, /?/ goes all they way back to Proto-AN *q (it may well have been *[?] by the time Proto-Oceanic developed); I'm pretty sure it's lost in all other Polynesian langs., but some (like Hawaiian) have developed /?/ < *k. The only cognates I recognize in Philip's list: To. 'au 'current' vs. au 'me' = Malay harus *qaRus vs. aku *aku Haw. IIRC au vs. a'u Digressing a bit, there are Austronesian languages (and surely others) that have automatic [?] onset to vowels, but when you add a CV-prefix, some words show /?/, while others have smooth transition-- e.g. of two homophones with initial [?]i... one may go to **ma?i... the other > **mai.... One is always suspicious of [?] between like vowels.