On vs Nous
On (3rd singular person) is formally used to refer to an undertermined person. But in spoken French, it is used instead of nous which, despite the way French is taught, is viewed as formal. Both sentences are equivalent:
- Nous allons à la plage. (We are going to the beach)
- On va à la plage. (We are going to the beach)
Tu vs Vous
Tu is the ‘you’ singular while ‘vous’ is the ‘you’ plural. But…
Using tu is called tutoyer quelqu’un and is the normal way to address someone.
Using vous is called vouvoyer quelqu’un and is used typically when there is a kind of hierarchy or distance (a student towards a professor and vice-versa, an employee towards his boss in some companies and vice-versa, a young person towards a more aged person) or between strangers or people who don’t know each other very well.
Both sentences below mean ‘you arrived early this morning’, but the first one uses the tutoiement while the other one uses the vouvoiement:
- Tu es arrivé tôt ce matin
- Vous êtes arrivé tôt ce matin