Interrogative pronouns (soru zamirleri) are used to ask questions. The main ones are:

• Kim: Who? (refers to people)
• Ne: What? (refers to objects, concepts, or actions)
• Hangisi: Which one? (implies selection from a group)
• Neresi: Where? / Which place? (refers to location)
• Kaçı: How many of them? (implies a part of a group)

Example: Kim geldi? (Who came?) Ne oldu? (What happened?)

Declension:

Interrogative pronouns also decline for case.

Kim (Who)

• Nominative: Kim (Who)
• Genitive: Kimin (Whose)
• Accusative: Kimi (Whom)
• Dative: Kime (To whom)
• Locative: Kimde (On whom, with whom)
• Ablative: Kimden (From whom)

Example: Bu kitap kimin? (Whose book is this?) Kimi gördün? (Whom did you see?)

Ne (What)

• Nominative: Ne (What)
• Genitive: Neyin (Of what) - Note buffer 'y'
• Accusative: Neyi (What - specific)
• Dative: Neye (To what)
• Locative: Nede (In what, on what)
• Ablative: Neden (From what, also means 'why')

Example: Neyi beğendin? (What (specific thing) did you like?) Neden bahsediyorsun? (What are you talking about? / Why are you talking?)

Hangisi declines by adding case suffixes after the '-i' (which is a possessive suffix): hangisinin, hangisini, hangisine, hangisinde, hangisinden.
Neresi declines similarly: neresinin, neresini, neresine, neresinde, neresinden.
Kaçı declines similarly: kaçının, kaçını, kaçına, kaçında, kaçından.

Other Interrogatives:

Note that words like 'Nasıl' (How?), 'Nerede' (Where?), 'Ne zaman' (When?), 'Niçin/Neden' (Why?), 'Kaç' (How many/much?) are interrogative adverbs or adjectives, not always pronouns, but are key for questions.