Questions & Answers about Cậu sút nhé.
In this sentence, cậu is a second-person pronoun meaning you, but it is not neutral in every situation.
It is commonly used:
- between friends
- between classmates
- with someone around your age
- in casual, familiar relationships
It can sound wrong if you use it:
- with strangers
- with much older people
- in formal situations
So cậu tells you something about the relationship: the speaker is addressing someone fairly casually and familiarly.
Also, cậu can have other meanings in Vietnamese in other contexts, but here it is clearly a pronoun.
Vietnamese often leaves out words that are obvious from context.
So if everyone can already see:
- the ball
- the goal
- the play happening right now
then the object does not need to be said.
A fuller sentence could include the object, but in natural speech people often shorten it. English does this too in some contexts, but Vietnamese does it even more freely.
So Cậu sút nhé. is natural if the listener already knows what they are supposed to kick or shoot.