Can you say Która jest twoja sukienka?
Well... in speech, I guess people can say that... but that doesn't sound too great to me :/
Is this a natural way of expressing this question in Polish?
Which case is this any why?
Everything here is in Nominative. The dress (or maybe even 'which dress') is the subject, and the pronon "wasza" behaves kind of like an adjective, so it stays in Nominative as well.
Er… where did wasza come from?
There's no trace of wasz… in the (current) original sentence.
It was probably one of the starred answers back when those comments were written (over 3 years ago). It's not now, it's not very likely.
Duo just rejected my translation"Która suknia jest twoja?"
Surely "dress" = "suknia" = "sukienka" here; the 'correct' "sukienka" is merely the diminutive of "suknia".
I wouldn't say "merely the diminutive", "suknia" sounds rather formal to me, like a wedding dress or a charity ball dress. But still, it's surely correct.
is "która twoja sukienka?" wrong?
Yeah, it misses the verb.