🗣️ Two phones become one live interpreter — offline, no account, $0

Tools & Scripts
, ,
1

:speaking_head: Two phones become one live interpreter — offline, no account, $0

31 languages · speech + translation run on the phones themselves · open source · works in airplane mode

two phones, one live interpreter
two phones, one live interpreter1200×900 199 KB

You talk. Your phone types it, sends the text across the room over Bluetooth, their phone translates it and speaks it out loud. Same in reverse. No internet, no account, no server — every word stays on the two phones.

the 30-second version

🎙️ you speak            →  📝 Whisper types it on YOUR phone
📶 Bluetooth LE          →  the text crosses the room — never a server
🌐 their phone           →  HY-MT translates it + 🔊 speaks it out
🔊 your phone            →  same in reverse — live, both directions

Everything runs on the phones: Whisper (OpenAI’s speech-to-text) and the translation model sit in the app. Airplane mode is not a problem — it’s the point.

the three modes — pick your moment

mode what it does pick it when
:speaking_head: Conversation 2–4 phones link up, each person hears their own language, Bluetooth headsets work, runs in the background real conversations — dinners, clinics, tours
:radio: WalkieTalkie one phone listens in two languages at once, auto-detects who’s speaking, talks in turns quick street moments — taxis, shops, hotel desks
:keyboard: Text classic translator, no microphone menus, signs, when it’s too loud to talk

which build to install

build pick it when the catch
:trophy: 3.0 beta 2 you want the crazy part: the new HY-MT 1.8B model scores above Google Translate on benchmarks, adds a WalkieTalkie widget + Tasker support + full-screen captions it’s a beta — expect bugs, and it won’t talk to older versions
:shield: 2.1.5 stable you want boring and reliable older NLLB model — good, not great

Both are free APKs straight from GitHub releases — not on the Play Store yet (3.0 stable is headed there, plus F-Droid).

the literal four steps

  • Install the APK from github.com/niedev/RTranslator/releases
  • First launch downloads the AI models (~1.2 GB, one time — do it on Wi-Fi before you travel)
  • Pick your languages and, if you like, connect Bluetooth headsets
  • Connect phones — Conversation mode finds nearby RTranslator users; accept, put the phone in your pocket, talk

The download is the only time it ever needs the internet.

the rare gems · the limits, plainly · the unlocks

:gem_stone: Rare gems

  • :busts_in_silhouette: The 4-phone swarm — one phone + one headset per person, up to 4 connected: everyone hears their own language at the same table, peer-to-peer, no server (maintainer-confirmed cap: discussion #67)
  • :headphone: The one-ear trick — a cheap mono headset leaves one ear free for traffic, the doctor, or the actual person in front of you (Conversation mode only)
  • :ear_with_hearing_aid: Live captions for deaf/HoH chats — v3.0’s full-screen text + per-message TTS button = the transcript IS the conversation; switch TTS off and it’s a subtitle aid
  • :robot: One-tap launch — beta 2 ships a home-screen widget and a Tasker intent for WalkieTalkie mode → stick an NFC tag on your desk and translation starts on tap
  • :tornado: The blackout kit — models are on the phone, so it works in disasters, borders, dead zones; preload before deployment and test the language pair first
  • :globe_showing_europe_africa: The hidden language drawer — 31 core languages, plus ~40 more under Support low-quality languages in settings

:warning: Limits, plainly

  • needs a phone with 6 GB RAM minimum (fast CPU helps — it’s running real AI)
  • beta means bugs; Bluetooth can drop; translation is turn-based, not simultaneous
  • “beats Google Translate” is the author’s benchmark claim — great for text, not yet proof for every noisy accent
  • not a certified medical interpreter — double-check medications, consent, and diagnoses the human way

:unlocked: The unlocks

  • 1.2 GB download crawls or fails in your region? → Sideloading guide: download the .onnx files on a computer, copy them to Android/data/nie.translator.rtranslator/files, launch — the app verifies and only re-fetches broken files
  • App dies in the background? → exempt it from battery optimization, keep it foregrounded for long sessions, carry a power bank
  • Robotic voice? → swap the system TTS engine (Google TTS is the recommended one) in Android settings, restart the app
  • iPhone in the room? → no iOS app, by the maintainer’s own choice (issue #22) — the planned self-hosted web translator covers text for iOS folks; voice stays Android-only

No signal, no SIM, no subscriptions — two phones and a sentence are enough.