I think it has to do with being morphophonemic: https://en.wikipedia.org/wiki/Phonemic_orthography#Morphophonemic_features https://en.wikipedia.org/wiki/Phonemi

I think it has to do with being morphophonemic: https://en.wikipedia.org/wiki/Phonemic_orthography#Morphophonemic_features https://en.wikipedia.org/wiki/Phonemic_orthography#Morphopho... "This means that the spelling reflects to some extent the underlying morphological structure of the words, not only their pronunciation. Hence different forms of a morpheme (minimum meaningful unit of language) are often spelt identically or similarly in spite of differences in their pronunciation."