What's the difference between "tú" and "usted"?

Hello, my name is Alejandra and the question I'll be answering now is: What's the difference between "tú" and "usted"? Choosing between "tú" and "usted" depends on the person with whom we are talking. In English we might add words like "Sir", "Madam", or expressions like "Excuse me", to address someone in a formal way. In Spanish, we don't necessarily require these words or phrases to make our speech more formal, because we have a specific pronoun for that. Some languages have this way of formal speaking, where we have two ways of saying the singular pronoun "you", as a way to show respect to people who are older than us or in positions of authority (not necessarily older than us). An easy to remember formula would be: When speaking to people our age or younger we use the pronoun "tú". When speaking to people in positions of authority we use "usted". When speaking to people who are older than us, but not necessarily in a position of authority, choosing between "tú" and "usted" will depend on the level of trust between you and the person. Here are a few examples: 1. First day of university. Classmates are all your age. You use the pronoun "tú" when talking to them, but you use the pronoun "usted" to talk to your professor. 2. Now, imagine the same context. First day of university. But you have a classmate who is 45 years old. You address him or her with "usted", just as you address your professor. And you use "tú" for everyone else, provided that everyone else is your age. 3. Imagine you are 45 years old, returning to college to get your degree. Most of your classmates are 20 years old or younger. But there is another person among them who looks your age. You will address all of your classmates with "tú". But you will address your professor with "usted" regardless of how old he or she is. I hope this cleared your doubts. Remember private sessions are also available and you can message me if you'd like me to be your teacher. See you around and have a nice day!