Learn Italian: La signora ha lasciato le chiavi nella borsetta. - The lady left the keys in the small bag.

It uses the diminutive suffix -etta. The base word is borsa (bag). By dropping the final -a and adding -etta, it becomes a 'small bag' or 'handbag'.

Why do we use nella here instead of in la?

In Italian, the preposition in (in) and definite articles like la (the) must combine into a single word. In + la always becomes nella. Since borsetta is feminine singular, it takes the article la.

Why does chiavi end in -i if it uses the feminine plural article le?

The singular word for key is la chiave. In Italian, nouns that end in -e in the singular always change their ending to -i in the plural, even if they are feminine. So la chiave becomes le chiavi.

Why does this sentence use ha for the past tense of lasciare instead of è?