In all languages:
Why
It is the word that often provokes people to lie, which eventually results in the lie being exposed and the word being used again, and again, and again, until the truth is eventually revealed.
The truth brings enlightenment to some and madness to others.
"Why" is the word first used when we became aware enough to have a sense of self.
"Why" is the perpetual search for truth, and the total consequences of truths are unforeseeable.
"Why" is the weapon to pierce lies, for although the truth may set you free, recognizing a lie for what it is will keep you out of bondage in the first place.
One "why" always leads to another.