I have Blue and Green JP versions and I've played through them, so I remember most of the gen 1 pokes names in JP. And I know names of a few of my favorites in JP just because I search for art of them on Pixiv and stuff (same with some characters like Drayden, etc.)
But for the most part I only play the game in English version so I don't have any reason to care about the JP names at all.
"Earth is a silly place. Half the world has no clean water. And the other half has so much, they poo in it."
I know a few of them. I know Keromatsu (Froakie), Harimaron (Chespin), Fokko (Fennekin) and Ninfia (Sylveon) even though it's pretty pointless to know those, since their JP names got revealed at the same time as (right before in Sylveon's case) their international names.
Official Zangoose of the Pokemon X board+Only member of my one-man team 3DS FC: 3609-1237-6725