THE RULES

WORDS that end with  o  in the singular, change to  i  in the plural

WORDS that end with  a in the singular, change to  e in the plural

WORDS that end with  e  in the singular, change to  i  in the plural:

o  ►  i

a ►  e

e ►   i

GIORNO => GIORNI  (day =>  days)

LIBRO => LIBRI  (book =>  books)

CASA => CASE  (house =>  houses)

DONNA => DONNE  (woman =>  women)

STUDENTE  =>   STUDENTI  (masculine: student)

LEZIONE  =>   LEZIONI  (feminine: lecture)

Nouns ending with  < o> usually are MASCULINE
The rule applies both to nouns (things) and adjectives (qualities)
 

GIORNO BELLO =>   GIORNI BELLI  (beautiful day => beautiful days)

LIBRO APERTO =>    LIBRI APERTI  (open book  =>  open books)

The rule applies both to nouns (things) and adjectives (qualities)

CASA MODERNA =>   CASE MODERNE (nodern house =>modern houses)

DONNA FAMOSA =>    DONNE FAMOSE (famous woman  =>  famous women)

Nouns that end with  < e > in the singular, change to < i > in the plural:
Some nouns ending with  < e > are masculine, other are feminine

The rule applies both to nouns (things) and adjectives (qualities)

STUDENTE INTELLIGENTE =>   STUDENTI INTELLIGENTI
(intelligent student => intelligent students)

LEZIONE INTERESSANTE =>   LEZIONI INTERESSANTI
(interesting lesson => interesting lessons)

GRAMMAR

CASA GRANDE   =>    CASE GRANDI
 
casa ends with a, the plural is  e  = case
grande ends with e, the plural is  i  = grandi


STUDENTESSA INTELLIGENTE = > STUDENTESSE INTELLIGENTI

studentessa ends with a, the plural is e = studentesse
intelligente ends with e, the plural is i = intelligenti
 

APPARTAMENTO ELEGANTE = > APPARTAMENTI ELEGANTI

appartamento ends with o, the plural is  i  = appartamenti
elegante ends with e, the plural is  i  = eleganti