Similar to Arabic “sun and moon letters”, I have designated two groups of letters within Moya. However, the distinction is unrelated to phonological assimilation and has everything to do with how the characters fit together in writing (especially calligraphy). So, the letters (except for “a”) fall into either the moyata (male letters) or moyana (female letters). The defining characteristic is the presence – or lack thereof – of the tapa (roof), which is present on the moyata but not the moyana.
Examples will follow.