"Koszula" is singular, "Koszule" is plural. The declension is the following: in singular: koszula, koszuli, koszuli, koszulę, koszulą, koszuli, koszulo; in plural: koszule, koszul, koszulom, koszule, koszulami, koszulach, koszule (the dictionary: http://sjp.pwn.pl/szukaj/koszula.html indicates the endings for the most problematic cases: " -uli, -ulę" for singular and "-ul" for plural). So:
Potrzebujesz koszuli? = Do you need a shirt?
Potrzebujesz koszul? = Do you need shirts? (But I admit that this one (Genitiv of plural) is a hard and probably the least intuitive (even for native speakers).)
Ta koszula jest niebieska. = This shirt is blue.
Te koszule są niebieskie. = These shirts are blue.
Mam koszulę. = I have a shirt. (note that the last letter is "ę" not "e").
Mam koszule. = I have shirts. (note that the last letter is "e").
I would appreciate if you give me a hint about the order in which you mention cases during declension( like which is which? abbreviated Latin names are quite enough Nom Gen Dat Acc Instr Voc, looks like I missed one) thank you
This particular, word Potrzebuje, requires Genetive - not the usual Accusative.
The verb 'potrzebować' needs object in genitive.
I don't know if there is a logical explanation for that, but here someone explained it http://mowicpopolsku.com/polish-grammar/cases/genitive/
Why do I hear N in koszuli? Is the last syllable pronounced this way or am I hearing something wrong? I thought it would be more like 'koshulee'...on google translate I hear the Lee sound but not here..is there a reason?