Guide

Study a language from your own PDFs and ebooks

Reading is one of the richest ways to build a language — a novel, a textbook, an article gives you far more words per hour than most video. The catch is the same as always: you look a word up, understand the sentence, read on, and lose almost all of it.

Most study tools can't help here at all. The popular ones are browser extensions tied to streaming video — they don't touch the epub on your reader or the PDF on your desktop.

Reading needs a review loop, not another highlight

The words worth keeping from a book are the ones you had to look up — but a highlight is a passive mark you'll never open again. To retain them you need to be asked, later, out of context, more than once. Doing that by hand (copying sentences into flashcards as you read) is slow enough that it pulls you out of the reading itself.

The better move: let something read the document with you and turn it into review automatically.

Doing it with Langcap

Drop an ebook or PDF in — an epub, a PDF article, a chapter — and Langcap mines it into short questions, each stitched back to the exact line or passage it came from. No transcription needed for text; it works straight from the document. A spaced-repetition scheduler brings each word back as it starts to fade, and Recall runs the question loop scoped to just that book or paper, so you can study one source at a time.

It runs entirely on your machine — your documents stay in your folders, no account, nothing uploaded, offline after the one-time setup.

What's supported

Drop in an epub and Langcap opens it as its chapter list, so you start with the chapter you're actually on rather than waiting on a whole book. A PDF comes in whole. Text is a full on-ramp for seven languages today — English, Spanish, French, German, Italian, Portuguese, and Chinese. (Japanese and Korean study from audio for now, with their text voice coming.) It's a young Windows beta and needs a Vulkan-capable GPU.