Formation of
Plural Nouns

If a word is masculine singular, change the last
letter to an i.  If a word is feminine
singular, change the last letter to an e if
it ends in a, or if it ends in e, change
it to an i.

Note:  Some nouns ending in
-co and -go may or may not insert an
h before changing the o to i.  There is
no gerneral rule for it.  All nouns ending in
-ca and -ga insert an h before changing
the a to e.  Nouns ending in an accented vowel
do not change for the plural. (la città (city)
becomes le città)  There are some masculine
nouns that end -a, and these nouns change the -a to
-i in the plural: il programma, il poeta, il pianete,
il pilota, il poema, il sistema.  The plural
of l'uomo (man) is gli uomini, while
the plural of la mano (hand) is le mani.