Jaka. It seems to translate fairly well to Esperanto "kiel" or Portuguese"Como". Can translate into English as "how", "like", or "as" in English, depending on context.
(I am not Polish, take that advice with a grain of salt!)
EDIT: As mentioned below by mihxal, the above is not 100% correct. Serves me right for making a call on a word I've used maybe 2 or 3 times!
Hmm, really? I've never heard the word used that way. That being said, I haven't spoken a lot of Esperanto, and what I have spoken is mainly with English speakers or Brazilians.
I'm used to hearing something in the figurative sense like "Kia hundo ne ŝatas marŝi!?" (rhetorical question) or the literal sense like "Kia hundo vi havas" (Germana ŝafhundo, pudelo ktp.)
I'll keep what you said in mind, though. There's a good chance you're right and I've just been speaking to people who have a bias based on their own natural language.
(Cetere, mi vere havas hundon (pudelo), kiu ne ŝatas marŝi! Li kaŝas sin sub la lito aŭ tablo kiam ajn ni diras al li "walkies!". Stranga besto!)
It never works.
Kim jest twoja żona? - but that is who is your wife - ( answer implies job, sometimes a name or nationality, ethnicity)
Kto jest twoją żoną ( identity question - this lady, name and surname)
Jaka jest twoja żona? ( description guestion, - adjectives or long describing sentences)
Która to twoja żona? ( which (of those ladies) is your wife?)
In Formal You, you have to always specify the subject, otherwise it looks as if you're talking about some 3rd person that should be known from the context. So "Jak się ma?" seems like a part of "A Julia? Jak się ma?"
So it will be "Jak się pan/pani ma?". A bit informal, but it's not like with every pan/pani you have to be strictly totally formal... after all, you address most people like that, it can be friendly.
Usually yes, because usually it is an "X is Y" sentence, and of course the part in Instrumental needs to be a noun phrase - a sole adjective would stay in Nominative. But here, in this question, "your wife" is the subject. The answer can be "Moja żona jest wysoka" or "Moja żona jest uroczą kobietą" (My wife is a lovely woman), etc. There's no reason to have "your wife" in Instrumental as she doesn't describe anything, it is her description that we ask for in the question.
Jaka jest twoja żona. There is no feeling in this sentence. So why do you not agree with "how is your wife" in the other cases you consider that the sentence is used in practice but in this exercise you create a new mold. I do not met such question in english. If i hear "what is your wife like" it sounds as answer "my wife looks like and alien". confused.
Actually, it's exactly the other way round. "twoja" is "Your wife, John" and "wasza" would be "Your wife, John and George" (yes, one wife for two husbands, so polygamy).
We accept both singular and plural 'you'/'your' in most sentences, but not in sentences like this one, rejecting "wasza" may make some people realize that important distinction.