"Piję szklankę wody."

Translation: I am drinking a glass of water.

[A477]

so literally a waters glass. comparing to romanic languages where for example in spanish you would say un vaso DE agua, polish eliminates the prepostition with the genitive case right?

[Jellei]

Right. It's good to always imagine this "of" (even if it's not literally there in the English sentence sometimes) which causes Genitive.

[Ollyfer]

I suddenly realised that in German, we do the same “mistake” at least from a semantic perspective (Ich trinke ein Glas Wasser -- I drink a glass' water). Only now that I was asked to translate it into Polish did I realise what a gibberish I say when translating it literally.

[BenjaminHo5]

So in the sentence, "On potrzebuje szklanki wody" the ending of szklank is different because potrzebuje puts it in genitive, right? Thanks for the help!

[Jellei]

Yes, exactly :)

[akikotsukamoto]

exactly speaking I do not drink a glass but drink water, but szklanka takes biernik case?

[claudiuas]

It would be different if it was a glass made of water?

[Okcydent]

„wodna szklanka ” or „szklanka z wody” or „szklanka zrobiona/utworzona z wody”

Compare: plastikowy kubek vs kubek plastiku.