PolyTypeCapabilities & accuracy
What runs in your browser, what the full app adds, and how accurate each conversion actually is — measured on real text, not estimated.
In your browser vs. the full PolyType
Everything below runs locally and privately — nothing you type is uploaded. The website is complete on its own; a browser extension and a macOS app extend the same engines beyond this page.
| Capability | This website | App / extension |
|---|---|---|
Phonetic keyboards — type by sound (privet → привет) | ✓ | ✓ |
Diacritic restoration — Serbian / Croatian / Bosnian (zasto → zašto) | ✓ | ✓ |
Latin ↔ Cyrillic conversion (Dobar dan → Добар дан) | ✓ | ✓ |
Fix a wrong keyboard layout — paste & convert (ghbdtn → привет) | ✓ | ✓ |
Recover ь / ъ a letter-map can't (bolshoe → большое) | ✓ * | ✓ |
| Works in every text field on every website | — | ✓ extension |
| Works system-wide, in every app | — | ✓ macOS app |
| Fix the layout as you type (no copy-paste) | — | ✓ macOS app |
| Private, offline, no account, no sign-up | ✓ | ✓ |
* The ь/ъ dictionary loads in two tiers — a light set right away, the full set in the background — so the page stays fast and gets more accurate after a moment. The browser extension and macOS app are in preparation.
Measured accuracy
Numbers below are measured on real word-frequency corpora (held-out bands), for the everyday case — pasting a sentence. We publish them openly, including where it's weaker.
Fixing a wrong keyboard layout
"Converts correctly" = your mistyped sentence becomes the right script. "Leaves English alone" = a real English sentence pasted by mistake is not mangled.
| Language | Converts your text correctly | Leaves real English alone |
|---|---|---|
| Russian | 99.9% | 100% |
| Ukrainian | 99.9% | 100% |
| Armenian | 99.5% | 100% |
| Georgian | 99.3% | 100% |
| Serbian | 92.9% | 100% |
Serbian is the hardest case: short Serbian words and English words collide on the keyboard, so a single isolated word is less certain — a fuller dictionary (the second tier) closes most of that gap. Whole sentences are reliable.
Recovering ь / ъ (Russian)
A plain letter-map cannot bring back the soft and hard signs. The full dictionary does:
| Dictionary tier | Words recovered | incl. ь/ъ words |
|---|---|---|
| Light (loads instantly) | ~84% | ~83% |
| Full (loads in background) | ~96% | ~96% |
Examples: bolshoe → большое, obyavlenie → объявление,
podyezd → подъезд, vyezd → въезд, semya → семья.
How we measured
Detection accuracy is tested against real word-frequency lists (OpenSubtitles), on frequency bands held out from the model, for both directions: national text typed in the wrong layout (should convert) and real English (should be left alone). The ь/ъ figures come from a 6,000-word Russian test set run through the same phonetic-skeleton index the desktop app uses. Everything runs in your browser; none of your own text is part of any measurement.
PolyType is part of ctrl8, a collection of small, local-first tools. Authored by Ilya V. Osipov.