Sedang language

Sedang is an Austro-Asiatic language spoken in eastern Laos and Kon Tum Province in south central Vietnam. The Sedang language has the most speakers of any of the languages of the North Bahnaric language group, a group of languages known for their range of vowel phonations.

Diphthongs
Sedang itself has 24 pure vowels: 7 vowel qualities, all of which may be plain ([a]), nasalized ([ã]), and creaky ([a̰]) and three of which /i a o/ may be both nasal and creaky ([ã̰]). While it does not have the length distinctions of other North Bahnaric languages, it has more diphthongs, between 33 and 55 vowel sounds all together. (The above set yields 50.) Sedang is thus sometimes claimed to have the largest vowel inventory in the world. However, other Bahnaric languages have more vowel qualities (Bahnar, for example, has 9) in addition to phonemic vowel length so the language with the record depends closely on how the languages are described and distinct vowels are defined.