🌍 Translation
Sentence-level translation across 16+ languages. Offline-first via bundled dictionary; cloud upgrade via Gemini Flash for richer phrasing when online.
📚 Two-Path Translation Engine
| Path | Engine | When | Quality | Latency | Offline |
|---|---|---|---|---|---|
| Offline dictionary | Bundled offlineDictionary.ts (4000+ word pairs × 14 locales) | Always tried first; sole engine when offline | Word-level: good. Phrase-level: limited. | <10ms | ✅ |
| Cloud (Gemini 2.5 Flash) | /api/v1/translate → Gemini Flash | When online + dictionary miss / sentence-level | Excellent — preserves tense, idiom, register | ~700ms | — |
The Prism AAC keyboard’s “translate this sentence” feature uses both: dictionary fallback ensures the device always responds, cloud upgrade kicks in when online for better phrasing.
🌐 Language Coverage
Bundled offline:
en · es · fr · pt · ja · zh · de · ko · ar · ro · uk · ru · it · nl
Cloud-only (uses Gemini’s 100+ language coverage when online):
hi · bn · tr · pl · vi · th · …
🩺 Why Offline-First Matters
- AAC users in school / clinic / remote settings can’t depend on Wi-Fi.
- Patient communication during home visits — clinician’s offline dictionary + premium TTS keeps the conversation going.
- School deployments — bandwidth is throttled or filtered; translation must still work.
🏗️ Architecture
POST /api/v1/translate { text, sourceLang, targetLang, mode? }
→ { translated, source, model }
mode: 'word' | 'sentence' (default: auto)Client-side path (in services/translateService.ts):
- If targetLang in offline dictionary: try local lookup → if hit + mode≠‘sentence’, return.
- Else call
/api/v1/translate(5s timeout matching/text/correct). - On timeout / error: return original text — never block.
🔄 Inter-Module Integration
- Prism AAC keyboard — “translate” toggle pre-translates outgoing speech.
- AAC chat — response auto-translated to the user’s locale before display.
- Mail — incoming non-locale messages get a one-tap translate-inline.
- Patient portal — UI auto-translates per the patient’s preferred language (cookie + browser detect).
💳 Plans
Available on every tier — translation is an accessibility primitive, not a billing surface. Cloud-translation usage is rate-limited on free tier (200 calls/user/day, same as autocorrect) to control cost.