Learn how to greet people in Spanish, at any time of day or night.
Polite phrases like “please” and “thank you” are the most important Spanish vocabulary you’ll ever learn. When you visit Spain, knowing just these few phrases will go a long way, even if the very next thing you say is ¿Hablas inglés?
The distinction between tú and Ud. is one of the most confounding aspects of Spanish, and one of the most basic. The influence it has on verb conjugations and pronouns is considerable,* but more than that, the choice of tú or Ud. is a matter of etiquette.
Titles like señor and señora are important in Spanish, and they are used somewhat differently than their English counterparts.