
Quick answer — Megumi Iwasaki voices Taichi in Kids on the Slope, Mami Misato in Yamada's First Time: B Gata H Kei.
Megumi Iwasaki voices Taichi (Kids on the Slope), Mami Misato (Yamada's First Time: B Gata H Kei).
Taichi is voiced in Japanese by Megumi Iwasaki.