The Role of Tone in Natural Languages

Contour tones are somewhat more likely to happen on long vowels. You often get like a falling tone or a rising tone in those. In the Athabascan languages, we have some languages that have tone and some languages that do not has tone. And what has happened is that languages without tone can have glottal, like ejectives as codas. But the languages with tone have gotten rid of all glottolic elements at the end of a syllable.