There are 20 letters and one digraph in the Mato alphabet:
The Mato part of the dictionary is arranged alphabetically according to the above order.
The letters are pronounced phonetically, with a few exceptions. The digraph ng represents the sound [ŋ]. The only Mato letter that does not occur in Tok Pisin is x. In the Tabares dialect of Mato, the x has four different sounds. At the beginning of a word, it represents a voiceless velar fricative [x]. Intervocalically, except when followed by i, it is pronounced as a voiced velar fricative [ɣ]. In the case where it is followed by i, it is also retroflexed [ɣ˞ ], giving the sound an r-quality. At the end of a word, x is never written, and is always pronounced with a glottal stop [ʔ] with the effect of attracting stress to the final heavy syllable. However, it is written when the sound surfaces in word-building, such as xalu ‘door’ versus xaluxinoa ‘its door’. Speakers of the Ramuk dialect pronounce the x as a glottal stop in all environments.
Mato has two diphthongs, ai and au. In rapid speech, au is often pronounced [o], and ai coalesces to [e] in closed syllables. Stress is predictable and usually falls on the penultimate syllable. Exceptions occur when heavy syllables (CVC, VC, VG, CVG, CVGC) attract word-final stress. Word-building processes also affect stress assignment, which ignore some suffixes and segments.