langsandlit:

person: plural formation in romance languages is relatively simple because the way you mark plurality is by either changing the word-final vowel or by adding -s.

me, an intellectual: neapolitan doesn’t just have one way to mark plurality in nouns and adjectives, in fact, as well as changing the vowel at the end of the noun, adjective or past participle, which by the way is often realised as /ə/, it also has a form of internal vowel mutation, which means that the stressed vowel in the middle of the word either breaks into a diphthong or raises to [u]. in addition to that, masculine and feminine items are usually differenciated in that feminine nouns did not undergo the same phonological development of etymological stressed /o/.