Submission by hestermani

Letra Letra is a 3D letter-learning adventure for pre-K kids ages 3–6. Players walk through a googly-eyed alphabet world, bumping into letter characters to hear them, spelling missing pets, and matching phonemes to letters. Three modes ship: Spell the Word, Find the Alphabet, and Match the Sound, plus a trophy shelf for repeat play. Before each game, the kid picks an avatar, a biome, and the letter case: Avatars: Kid, Car, Rocket Biomes: Park, Moon Letter case: UPPERCASE, lowercase, Mixed Plays in any browser, installs as a PWA, and works offline. Try it: https://www.playletra.com The Problem Most pre-K alphabet apps are flat 2D tapping games with stock TTS, and most ask non-readers to read on-screen instructions just to navigate. Letra is the opposite: a tactile 3D world where every prompt is voiced, so a child who cannot read yet can still drive every screen alone. Big buttons, generous proximity collection, voice-on-hover menus, and a hint timer that gently re-orients instead of scolding, all designed around one core assumption: the user cannot read yet. ElevenLabs ElevenLabs voices every line in the game: every letter name, every phoneme, every prompt, and every celebration, all in one warm, consistent custom narrator voice, Marissa. The full corpus of roughly 90 short MP3s is pre-baked at build time, so a child’s 40th replay costs zero tokens and starts instantly from cache. Token economics flip when the audience replays, and a 3-year-old will replay the same letter 40 times in a session. Without ElevenLabs, the game falls back to the browser’s Web Speech. It works, but it does not feel like a friend. Zed Zed’s agentic editor wrote the majority of the React shell and the three.js engine, including geometry, lighting, and the per-frame loop. It also handled the input layer, including keyboard, gamepad, and on-screen joystick support, plus the trophy state machine and the biome registry. I drove the design and kid-UX judgment calls, (with help from my four-year-old assistant): proximity collection radius, hint phrasing, joystick ergonomics, and voice-on-hover. ⸻ Source: https://github.com/billums123/letra