Who why what where when how? Yes/no?

As with most things in PF, an affix does it.

This can then be used to ask many questions:

Who:

hit-past-ret-atom person-?(nom) me(Acc)     => what person hit me?

Why (from what cause?):

hit-past-ret-atom he(nom) me(acc) reason-?(elat)     => he hit me (for what reason)?

Why (to what end?):

hit-past-ret-atom he(nom) me(acc) reason-?(term)     => he hit me (to what end)?

What:

eat-past-ret-atom you(nom) thing-?(acc)     => what (thing) have you eaten?

Where:

be-past-ret you(nom) place-?(loc)     => where (what place) have you been?

When:

go-past-ret you(nom) that place(term) time-?(loc)     => when did you go there?

How:

travel-past-ret you(nom) that place(term) method-?(instr)     => how (using what method) did you travel there?

Which:

bite-past-ret these(det) dog-?(nom) you(acc)     => which of these dogs bit you?

Yes/no questions can be done either with an idiom ("tell me that you ate an apple") or by attaching the question-affix to the verb :

eat-past-ret-? you(nom) apple(acc)