Breakdown of Widziałem piosenkarkę, którą lubisz.
widzieć
to see
lubić
to like
który
which, who (relative)
piosenkarka
female singer
Questions & Answers about Widziałem piosenkarkę, którą lubisz.
Why do we use którą here instead of the base form który or która?
The word for "which" or "that" has to match the gender of the noun it replaces, but its case depends on its job in its own part of the sentence. It refers to the feminine noun piosenkarka, so we start with która. However, because it is the direct object of lubisz (you like her), it must take the accusative case, changing która to którą.
In English, I can just say "I saw the singer you like" and leave out the word "that." Can I do this in Polish?
No, you can never drop the relative pronoun in Polish. You must always include którą (or whichever form is correct for the sentence), and you must always separate the two parts of the sentence with a comma right before it.
Why does piosenkarka change to piosenkarkę in the first half of the sentence?
Piosenkarka (female singer) is a feminine noun. Because she is the direct object of the verb widziałem (I saw), the noun takes the accusative case. For feminine nouns ending in -a, that means changing the ending to -ę.
How do we know the person speaking is a man?