Used as a Question
Depending on the intonation, 누구 can mean either 'who' or 'somebody'. If the sentence starts with a high pitch and ends with a downward intonation, then it is an interrogative pronoun meaning 'Who ... ?' However if the rising intonation comes at the end, it is a indefinite pronoun meaning 'somebody.' See the examples below
|누구 왔어요?||Up and then down||(insert audio)||Who came?|
|누구 왔어요?||Gradually rising||(insert audio)||Did somebody come?|
Used in Declarative Sentences
When 누구 is used in declarative sentences it is a indefinite pronoun meaning 'somebody.'
누가 is 누구 plus the subject marker 가.
As an interrogative pronoun:
As an indefinite pronoun
Common phrases using 누구