Wagnaria!! - Season 3 Episode 7 Goodbye Yamada
Overview: Staying over at Sōta's house, Aoi explains her backstory about being constantly forced to study by her mother, inevitably pointing out the reason she ran away was because Kirio ate her natto. As the other staff members try to convince Aoi to return home over the next few days, Popura asks Kirio to bring over his mother, Kikuno, who is revealed to have trouble talking with others clearly to the point that her children need a manual to understand her.