The number of "your" is contextual in English. If you are talking to one person, it is singular, two and it is plural. If you mean one of two people you are talking to, you'll be looking at him or her. You can, of course, for emphasis employ constructions like "both of you" or "all of you", but only when necessary for clarity, which is relatively rarely. The French manage with "vous", the Germans with "Sie" to represent either singular or plural. I think the very fact that you translate "vester" as "your" demonstrates that you understand that. If you had put "our" you'd have got a little message from our friend Duo.