less of a wisdom and more of a headcanon but sanctuary kind of implies wataru wasnt raised in japan (other stories also imply this, in summer vacation wataru brings up already having acted overseas as a child) and its rlly interesting because thanks to i7 we know how eguchi voice acts an english accent and that thats not wataru has, wataru is just doing... theater-y overenunciating

so imo they were raised bilingual (or more) in japanese and the main language of wherever they grew up. and i just wanna raise the possibility of wataru being french canadian again.