Ah Ha! My browser renders the Wikipedia mark as a square, so it means that the symbol as written cannot be handled. This also happens when I go to Japanese and Chinese sites, since I have not added the conversion capability to my programs.

Looked through my cds and books and didn't find anything other than ' used for the glottal stop.

I looked in "The Navajo Language" (dictionary and grammar, a monster volume for a very complex language) and found the ' used. I know almost nothing of the language, but it seems that extended or stressed vowels are written as doubled letters, rather than using a macron.

Not pertinent here, but I have found much mis-information, and speculation, put forth as gospel in Wikipedia. I would never use it as a reference.

Mudcat down again, can't post. Try again later.