Orthography
As stated above, vowel length is contrastive. What would be written phonetically as a: is represented by aa. All long vowels are written this way. All alveolars (/t/, /d/, /n/, /nd/) are dental-alveolars. They are represented in the orthography by t, d, n and nd. The /j/ sound is represented by y. The complete orthography of Mbula is as follows:
a e i o u b d g k l m mb n nd ŋ ŋg p r s t w z y
A E I O U B D G K L M Mb N Nd ¿ ¿g P R S T W Z Y
Read more about this topic: Mbula Language