Kelner dodaje cukier, ale ja nigdy nie piję słodkiej herbaty.

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Breakdown of Kelner dodaje cukier, ale ja nigdy nie piję słodkiej herbaty.

• herbata: the tea
• ale: but
• nie: not

Questions & Answers about Kelner dodaje cukier, ale ja nigdy nie piję słodkiej herbaty.

Why is cukier not changed in the sentence Kelner dodaje cukier? Shouldn't the direct object have a different ending?

In Polish, masculine inanimate nouns in the singular have the same form in the nominative and accusative cases. Since cukier (sugar) is a masculine inanimate noun and here functions as a direct object, its accusative form is identical to its nominative form: cukier.

Why is the phrase słodkiej herbaty used instead of słodka herbata after nie piję?

After a negated verb in Polish, the direct object usually takes the genitive case. Here, nie piję (“I don’t drink”) requires the genitive, so słodka herbata (nominative) becomes słodkiej herbaty (genitive feminine singular).

What role does the word ja play in ale ja nigdy nie piję? Can it be omitted?

Polish verb endings already indicate the person (here, 1st person singular), so ja (“I”) is grammatically redundant and can be omitted:
nigdy nie piję słodkiej herbaty.
It’s included only for emphasis or to contrast with the waiter’s action.

Why is there no pronoun before dodaje in the first clause?

Like most Slavic languages, Polish often drops subject pronouns because the verb ending signals the subject. Dodaje is 3rd person singular (“he/she adds”), so you know it’s “the waiter” (Kelner) without saying .