"Jij bent tweetalig."
Translation:You are bilingual.
Not really sure what you're getting at with the gender of the person being addressed but whether you're speaking to one or multiple persons, and whether that person/those persons are male, female or a mixed group, the translation will always be jij bent tweetalig
You may be right, I may be mistaken.
When talking about a woman from Russia I would say "zij is Russische" and in case of a man "hij is Russisch". I apply the same logic to other things as well. Now you mention it I am starting to doubt whether that is correct. I cannot find any definitive reference that says "zij is Russische" is correct (though I do see it used at lot, but that does not make it correct).
So if anyone can give me a definitive resource explaining this matter I would be most interested.