In Italian articles match the noun they relate to, both by gender (masculine or feminine) and by number (singular or plural): for example, translating the lady and the man different articles have to be used (la donna and l'uomo), as well as for the cat and the cats (il gatto and i gatti).
Furthermore, Italian language uses articles more often than English: general nouns and numerals sometimes require them, whereas in English they are usually omitted.
There are two types of articles: definite, or determinate and indefinite (determinativo and indeterminativo).
The definite article
In Italian a definite article (l'articolo determinativo) is used before a noun when referring to a particular person, animal, etc. In Italian the definite article has different forms because it must match the gender and number of the noun it modifies.
Masculine definite articles (lo ,il, l', gli, i)
Lo (masculine, singular) / Gli (masculine, plural)
Lo / Gli are used before nouns starting with a z, nouns starting with clusters s + consonant (sb-, sc-, sd-, etc.), gn-, pn-, ps-, and i plus a vowel.
lo zoccolo (the clog) / gli zoccoli (the clogs)
lo studente (the student) / gli studenti (the students)
lo psichiatra (the psychiatrist) / gli psichiatri (psychiatrists)
lo pneumologo (the lung specialist) / gli pneumologi (the lung specialists)
lo gnomo (the gnome) / gli gnomi (the gnomes)
lo iettatore (the jinx) / gli iettatori (the jinxes)
Quintus wrote:Although it's possible to use gl' before a vowel it would be advisable not to do it, because this type of elision is very very rare, except when the vowel is an "i" followed by any consonant. An example is "gl'impostori" (the impostors), which can be seen sometimes in literary works.
Il (masculine, singular) / I (masculine, plural)
Il / I are used when the noun starts with any consonant not belonging to the previous case.
il ramo (the branch) / i rami (the branches)
L' (masculine, singular) / Gli (masculine, plural)
L' (masculine, singular) / Gli are used with nouns starting with a vowel or the letter "h".
l'occhio (the eye) / gli occhi (the eyes)
l'hotel (the hotel) / gli hotel (the hotels)
Feminine definite articles (la, l', le)
La (feminine, singular) / Le (feminine, plural)
La / Le are used with nouns starting with a consonant.
la casa (the house) / le case (the houses)
la zuppa (the soup) / le zuppe (the soups)
L' (feminine, singular) / Le (feminine, plural)
L' / Le are used with nouns starting with a vowel.
l'ala (the wings) / le ali (the wings)
The indefinite articles
The indefinite article (l'articolo indeterminativo) is used with singular nouns only when it refers to an unspecified person, animal, etc. It has different forms because it must match the gender of the noun it modifies.
Indefinite articles (una, un', uno, un)
Una is used for feminine nouns beginning with any consonant
una mela (an apple )
una storia (a story)
Un' is used for feminine nouns beginning with any vowel
un’arancia (an orange)
un’audizione (an audition)
uno is used before nouns starting with a z, nouns starting with clusters s + consonant (sb-, sc-, sd-, etc.), gn-, pn-, ps-, and i plus a vowel.
uno straccio (a cloth)
uno zaffiro (a sapphire)
uno pseudonimo (an alias)
uno pneumologo (a lung specialist)
uno iettatore (a jinx)
uno gnomo (a gnome)
Un is used for all other masculine nouns
un pesce (a fish)
un autore (an author)