Doko Demo Issyo: its lineage, descendants, and standing in Japan
01What this origin is
Doko Demo Issyo, released by Sony Computer Entertainment for the PocketStation in 1999, established the taught-vocabulary companion: you feed a small character words and phrases with no fixed script, and it parrots them back later, unprompted, inside conversations you never wrote, producing results that range from nonsensical to eerily well-timed. It is the origin of the lineage of games where the entertainment is not authored dialogue but the unpredictable echo of what you personally chose to teach.
02Sources
03Buried gems that carry this root
Sashinomi Suika-chan Buried gem
Per Steam's own listing, this is a word-play simulation about trading idle small talk with the oni Suika Ibuki at a bar, teaching her words, hearing rumors, filling out the shop's menu and treating her to food. This is stated up front as a Touhou Project derivative work. Mechanically, you teach Suika words, people, food, anything, serious or joking, and those words later surface unprompted inside her conversation, producing results ranging from nonsense drunk talk to coincidences that land uncannily well; teaching food-related words expands the bar's menu, which you can then buy her. Made and self-published by the solo doujin creator ISY, whose twelve-title Steam catalogue is entirely small, single-character Touhou derivative works, including one this site has covered before, 寒いから鍋食いたいね女苑ちゃんと！！ (Nabe with Joon), a fact disclosed here rather than left unmentioned. Priced at ¥700, it is Positive at 100 percent across 15 reviews (15 positive, 0 negative per Steam's own review API), a paid title, not free, fully launched and not in Early Access, with no AI-generated-content disclosure and Steam's content descriptors completely empty. It supports Japanese only. Of its 15 reviews, 11 are in Japanese and just 1 is in English; Japanese players themselves compare it to Doko Demo Issyo, the PocketStation classic built around teaching a character vocabulary that comes back unpredictably.