Modern Standard Lemohai has a so-called “pure” vowel system, consisting of five oral and five nasal monophthongs. These keep their full value in all circumstances. In theory, they are never swallowed-up and cannot form diphthongs or triphthongs. Where two monophthongs meet, a slight hiatus is sounded between them. So words like Mohai and Tekuo consist of three syllables not two.
In rapid or colloquial speech, diphthongs will sometimes be encountered, though the practice is non-standard.
Oral monophthongs: a, e, i, o, u = /a, ɛ, i, ɔ, u /
Nasal monophthongs: an, en, in, on, un = /ã, ɛ̃, ĩ, , ɔ̃ , ũ/
Nasal vowels are sounded in the same place as their oral equivalents in the standard language. They are not permitted before sonorants. When compounding therefore, nasal vowels become oral in this position. Before a labial b or p in the same word, nasal vowels are written Vm. This also applies on compounding.