By- Claudia Quesito
As you probably know from your very first Italian classes, as a general rule, to make a singular noun plural, you change the final letter (-a becomes –e; -o and –e become –i).
There are some super easy nouns, the ones that do not change when becoming plural: nouns ending with an accented syllable (università), a consonant (computer), –i (analisi), abbreviations (moto, short for motocicletta), and monosyllabic words (re).
And then, there are some nouns that require extra attention. Let’s consider the word lago (lake), which is masculine/singular and whose plural form is laghi. Or fuoco (fire), which turns into fuochi. Where does that –h– come from? Well, nouns ending in –go –or –co turn to –ghi or –chi in order to maintain the hard /k/ or /g/ sound, but only if their stress falls on the second to last syllable. If the stress falls on the third to last syllable, the extra –h– is not needed, and so medico –doctor, turns into medici. You might wonder how you are supposed to know where the stress falls.
Don’t get stressed out: the majority of words follow the first pattern (stress on the second to last syllable). Little by little, you will learn which nouns do not need it. One very notable exception to this rule is amico, which becomes amici in the plural despite having its stress on –mi. At this point, you might be relieved to know that – when it comes to feminine – all nouns ending in –ga and –ca form their plural with the extra –h– (–ghe or –che).
Finally, some nouns have a completely irregular plural form: uomo becomes uomini, dio turns into dei, among the others. Some others form their plural by changing gender: uovo (egg), for instance, which is masculine in the singular, becomes uova in the plural; and miglio (mile) becomes miglia.
As always, when learning a language, i risultati si ottengono con la pratica (practice makes perfect). You learn the rules, you try to make sense of the irregularities, if possible, and you memorize the most important exceptions. And then you just practice, sometimes make mistakes, and learn from them.