Individual developer based in Tokyo. Solving everyday frictions that Japanese-native users feel but rarely talk about.
An iOS app for people who struggle with "words not coming out" (kotoba ga denai) in everyday conversation — a common social anxiety in Japan that doesn't have a dedicated practice tool yet.
The app provides a safe, judgment-free AI conversation partner where users can practice low-stakes daily scenarios (first meetings, small talk with colleagues, etc.) and gradually build confidence through inhibitory learning (exposure-based anxiety reduction) and enactive mastery (Bandura's self-efficacy theory).
Self-hosted real-time voice infrastructure on AWS for low-latency conversational AI. Cloudflare Workers as the API gateway for cap management and API key isolation. Subscription handling via RevenueCat.
In Japan, "言葉が出ない" (lit. "words don't come out") is a phrase nearly everyone has used at some point — describing the moment when you want to say something but can't get it out, often in stressful or unfamiliar conversations.
Despite being a widely shared experience, no dedicated practice tool exists for Japanese speakers. Existing apps target English learners (Speak, Duolingo) or job interview prep (SpeakViz), or are non-coaching AI chat companions (Cotomo). None of them solve the specific need to practice everyday Japanese conversation in a safe, repeatable environment with structured feedback.
KotobaGaDenai fills this gap with a fast-follow + quality strategy: borrow the best mechanics from existing apps (grade visualization, streak gamification, scenario-based prompts), then layer in what's missing (real-time bi-directional voice, judgment-free space, daily conversation context).