Learn Italian: Il cane è pericoloso, tu non stai attento. - The dog is dangerous, you are not paying attention.

In English, we say "you are paying attention" or "you are careful," but Italians use the set phrase stare attento (literally "to stay careful" or "to stay attentive"). Because it's a fixed expression, you must use the irregular verb stare rather than essere (to be).

Would stai attento change if I were talking to a woman?

Yes, it would! Even though it's part of an expression with the verb stare, the word attento acts like a normal adjective and must agree with the person it describes. Because it ends in -o here, we know the "you" being spoken to is male. If you were talking to a female, you would say tu non stai attenta.

Why is the pronoun tu included if stai already means "you"?

In Italian, subject pronouns like tu are usually dropped because the verb form (stai) already tells us who is doing the action. Including it here adds a bit of contrast or emphasis, like saying: "The dog is dangerous, and you are not paying attention."

Is pericoloso related to the word for "danger"?