Cymbra Lingua by NEETROF

Cymbra Lingua highlights, right on the page you are reading, the English words you do not know yet — without changing the layout. A percentage tells you how much of the text is familiar, counted from what you actually marked rather than guessed.

Click a highlighted word for its translation, its dictionary form and how rare it is in everyday English, then decide: "I know this", "+ Deck" to review it later, or "Ignore". Select several words and press Alt+L to capture a whole phrase with the sentence it came from.

The cards you build are reviewed in a panel, beside your reading or in the sidebar, with spaced repetition that picks the moment for you.

Read your own books too: import your DRM-free EPUB files into the extension's library and read them offline with the same highlighting, page by page — on an e-ink tablet as well. Your books stay on your device.

The analysis is local. The dictionary and the engine run in your browser: no page you read is ever sent anywhere, and the extension works offline. With no account and no extended translation, it makes no network request at all.

Extended translation (optional, off by default, on Chrome, Firefox for desktop and Android, and Safari): your selection is translated in its sentence, on your device, by the Firefox Translations engine. Turning it on downloads the translation model (25.8 MB) from Cymbra once; the text of the pages you read still never leaves your device. Turning it off deletes the model.

Create a Cymbra account if — and only if — you want your words and cards on your other devices. That is the only thing that leaves your machine, and you can erase it from Settings without deleting your account.

The interface is in French: Cymbra Lingua teaches English to French speakers. It is also on Chrome and on Safari (iPhone, iPad, Mac).