How to Write Long Vowels

If you have lots of vowel contrasts, vowel qualities rather, that might also traditionally be marked by accents, then you're in a world of hurt. Navajo uses an acute accent for high tone and doesn't mark the vowel at all for low. That's what La Don does if we're going to talk about invented languages. What Mandarin Pinyon does this, too. Anything else about tonogenesis? No, not really. I think people can read the paper. Or promise the paper. Yeah.