Formality in Spain
Spanish has four second-person address forms — each with matching verb endings and object pronouns:
• tú — singular informal
• vosotros/as — plural informal ( Spain only ; Latin America uses ustedes for all plural)
• usted (Ud.) — singular formal
• ustedes (Uds.) — plural formal in Spain
Choosing the wrong form sounds odd — too stiff with friends or too casual with a doctor. Follow the other person’s lead and default to usted when unsure in service settings.