Who?

The word who derives from the Old English hwā. The spelling who does not correspond to the word's pronunciation /huː/; it is the spelling that represents the expected outcome of hwā, while the pronunciation represents a divergent outcome – for details see Pronunciation of English ⟨wh⟩. The word is cognate with Latin quis and Greek ποιός.

The forms whom and whose derive respectively from the Old English dative and genitive forms of hwā, namely hwām and hwæs.