.

Actually, i been wondering it why though...
I mean Gen didn't start speak in pig latin untill the treasure island arc (probably).

He might be doing some sort of wordplay in Japanese, and that’s how they decided to translate it ... an odd but interesting choice

actually, i think he's been speaking like that since the beginning, but i might be wrong. in the anime, he speaks like how he does now in the manga, for example he says "eally-ray"(ji-made) instead of "really"(majide) if i recall correctly. it might just be the earlier translators being considerate of us or if the anime just decided to adapt the habit early, but it's part of his character as a mentalist, like it shows that he knows how to play with his words. i hope that makes sense :)

Ohhhhhhh ok thanks!!