Regarding your answer for "sa k fe sa" meaning "why" - can you as a 'why' question with is. "Why didn't you go?" I can say "POUKISA OU PA TE ALE" or "SA K FE SA OU PA TE ALE "?

If you choose to use 'Sa'k fè sa', you should write it without "sa":

1.
Sa'k fè ou pa te ale?
Why didn't you go?

other examples:

2.
Sa'k fè w kontan konsa?
Why are you so happy?

3.
Sa'k fè ou pa't di l sa?
Why didn't you tell him/her that?

Remember the Creole term Se sa'k fè - that is why? see link.

Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words