I think I'm struggling in something. Now when we say a sentence like "You are a happy human" we translate it as "Sen mutlu BIR insan" where bir came after the adjective. What about this sentence; why did we put bir before the adjective and said "Sen bir Alman vatandaşısın" instead of "Sen Alman bir vatandaşısın"???
Oh, I remember! There was something about compound words in the tips and notes. How do you form Turkish compound words? Very easily. You take two nouns (say, süt and para), put the first one (which is going to be an attribute to the second) before the second without changing it and when it comes to the second, you only have to add ı (or i, u, ü depending on the last vowel) to the word. So, there you have it: süt parası - the milk money (some kind of social security payment for little children).
I think it's the ending we've learnt about in the possessive skill. This ı (or sı after a vowel) which follows 4-way vowel harmony is supposed to show that the noun it is applied to belongs to something. But I'm not sure, of course. It would be great if some of the moderarors gave us the correct answer.