What about tu

Question

Hi I am a bit confused between vuestro and tu for yours.  Could I say 'El chico es tu primo'?Thanks

Answer

Hola Bernie
yes, you could say:

El chico es tu primo.
The boy is your cousin.

But this possessive "tu" is referring to "your" talking to just one person. However, when we say:

El chico es vuestro primo.
The boy is your cousin.

the possesive "vuestro" is referring to "your" talking to more than one person. 
Imagine two different situations:
1. you are with your friend, and you say to her:
¿Es ese tu hermano? (Is that your brother?)
Here you use the singular possessive "tu" because it is only one friend you are talking to.
2. You are with your friends Mark and John, and you say to them both:
¿Es ese vuestro hermano? (Is that your brother?)
Here you are using the plural possessive "vuestro" because you are talking to both of them.
What makes it a bit difficult to understand it that in English you just have one word for this possessives, whether you are using a singular "your" or a plural "your", it is always your. We have two: tu and vuestro. 
I hope this clarified it.
Saludos
Inma

Answer

Thank you