YOU SAID:
What in the world is the reason for this
INTO JAPANESE
いったい何が原因なのでしょうか
BACK INTO ENGLISH
What on earth is the cause?
INTO JAPANESE
一体何が原因なのでしょうか?
BACK INTO ENGLISH
What could be the cause?
INTO JAPANESE
何が原因でしょうか?
BACK INTO ENGLISH
What could be the cause?
That didn't even make that much sense in English.