Learn Italian: Avvicinati al tavolo, per favore. - Come closer to the table, please.

Avvicinati is an informal command (imperative) using the reflexive verb avvicinarsi (to approach or come closer). When giving a positive command to someone you call tu, Italian rules require you to attach the pronoun directly to the end of the conjugated verb. So, avvicina (come closer) plus ti (yourself) becomes avvicinati.

Why does the sentence use al instead of just pointing to il tavolo?

The verb avvicinarsi requires the preposition a to indicate what you are moving closer to. Since tavolo is a masculine noun that takes the definite article il, the preposition a and the article il combine to form the single word al.

I often see tavola used for table. Why is it tavolo here?

Tavolo is the general word for the physical piece of furniture, like a desk or an empty dining table. Tavola is specifically used when a table is set for a meal, such as when someone calls out that dinner is ready (a tavola!). Since this sentence is just asking someone to physically move toward the piece of furniture, tavolo is the right choice.

How would I say this to a group of people instead of just one person?