Neapolitan can be particularly challenging for Italians to understand because of the way number and gender are expressed - in Italian the final vowel changes when a word is pluralized and that change is determined by the gender of the word (whether it's masculine, feminine, or neuter). In Neapolitan usually the accented vowel changes, for example "loungo (masc.) and "lunga" (fem.). Because the final vowel is often dropped in Neapolitan, this often obscures gender, meaning that looking to the article is often helpful in determining gender rather than the ending. For example, o' guaglione becomes e' guagliune.

Feminine plurals often involved the doubling of the initial consonant as well.