[RadioKid]

>ヤッパ "I knew it!" (yappa)

Wrong. In this case, ヤッパ means some kind of blade (knife or sword) to kill. This is the reason why it is written in KATAKANA.

"ヤッパ：YAPPA" is the word used only in the dark side of Japan. I have never heard this word in my real life.

Google translator misunderstand YAPPA as RAPPA (trumpet).

My translation is .....

I can not forgive the guy who turns swords to other person with such crazy reasons.