وَتَخْتَلِفُ مِنْ جِهَةِ أَنَّ الْمَطْلُوبَ بِكُلٍّ مِنْهَا تَصَوُّرُ شَيْءٍ آخَرَ
They differ because each asks for the conception of a different kind of object.
The first analytical question is what information is missing? Is the speaker seeking a name's explanation, an identified person, a choice between candidates, a quantity, a condition, a location or a time? The missing information determines the interrogative's specific force.
Thus these words cannot be reduced to simple English equivalents such as what, who or when; the distinctions in the kinds of knowledge requested matter.
ExpressionObject requested
māExposition of a name or essence
manPerson or individuating description
ayySelection among shared candidates
kamNumber
kayfa / aynaCondition / place
matā / ayyānTime
annāHow or whence, according to use