Learn Spanish (Spain): Señor, ¿quiere ver el menú? - Sir, do you want to see the menu?

When you are talking directly to someone, you just use Señor, Señora, or Señorita. You only add el or la when you are talking about them, for example: El señor quiere ver el menú (The gentleman wants to see the menu).

Why is the verb quiere used here if the translation says 'do you want'?

Because the speaker is using the formal 'you' (usted) to be polite to the customer. In Spanish, usted always uses the same verb endings as he and she (él and ella). The word usted is left out here, but we know it means 'you' because they are talking directly to the Señor.

Why doesn't the second verb change to match the person? Why is it ver?

When two verbs go together to form one idea like 'wants to see', only the first verb is changed to match the person (quiere). The second verb stays in its basic, unchanged dictionary form, which is called the infinitive (ver).

Why does the upside-down question mark appear after the comma instead of at the very beginning?

In Spanish, the inverted question mark (¿) goes exactly where the actual question begins. Since Señor is just a greeting to get the person's attention, the question part officially starts at quiere.