Learn Polish: Jakie aplikacje zainstalowałeś, żeby czytać po polsku? - What apps did you install to read in Polish?

In English, we often just use the infinitive ('to read') to show purpose. In Polish, you must use the conjunction żeby ('in order to' or 'so that') followed by an infinitive verb like czytać. Also, notice the comma before żeby - it is mandatory in Polish grammar when introducing a new clause.

Why is it jakie aplikacje instead of co aplikacje?

When 'what' is used to describe a noun (like 'what apps' or 'what book'), Polish uses the adjective jaki (what kind of / which) rather than the pronoun co (what). Because aplikacje is plural, we use the plural form jakie.

How would the sentence change if I were asking a female friend?

The verb zainstalowałeś (you installed) has a masculine ending. If you are asking a woman, you need to change it to the feminine past tense form: zainstalowałaś.

Why is it po polsku and not just polski?

When you talk about doing an action in a certain language (like speaking, reading, or writing), Polish uses po plus a special adverb form of the language. So, 'in Polish' is always po polsku, while polski is just the adjective used to describe nouns, like język polski (the Polish language).