Learn Italian: Stasera festeggiamo il mio compleanno al ristorante. - Tonight we celebrate my birthday at the restaurant.

Stasera is a common contraction of questa sera, which literally translates to 'this evening'. It is the standard everyday way to say 'tonight' in Italian. You will also see this exact same pattern with stamattina for 'this morning'.

Why does the sentence use the present tense festeggiamo for an event happening tonight?

In Italian, the present tense is frequently used to talk about confirmed plans in the near future. While English uses phrases like 'we are going to celebrate' or 'we are celebrating', Italian comfortably uses the simple present tense festeggiamo. Additionally, because the verb ends in -iamo, it already includes the meaning of 'we', so the pronoun noi is left out.

Why do we need il before mio compleanno?

Unlike English, Italian almost always requires a definite article like il (the) before a possessive word like mio (my). You are literally saying 'the my birthday'. The main exception to this rule at this level is when you are talking about singular family members, such as mia madre (my mother), which drops the article.

How would I state the actual date of my birthday using what we are learning in this lesson?