Glossa is a web-based language learning app that lets you upload your own PDFs and EPUBs and read them in 13 languages with click-to-translate, audio narration, and built-in spaced-repetition vocabulary practice. It turns any book you already want to read into a graded reader for the language you are learning.

What languages does Glossa support?

Glossa supports 13 languages: English, Spanish, French, German, Italian, Portuguese, Dutch, Swedish, Norwegian, Danish, Polish, Russian, and Turkish. Word difficulty is scored from corpus frequency data, so coverage quality tracks how much text a language has in that corpus. Glosses and translations can be shown in 18 languages, those 13 plus Chinese, Japanese, Korean, Arabic, and Hindi. More languages are in preparation.

Can the translations be in my own language instead of English?

Yes. Glosses and sentence translations can be shown in 18 languages: the 13 you can learn plus Chinese, Japanese, Korean, Arabic, and Hindi. Glossa uses your native language by default and you can change it for each book, so a Chinese speaker can read an English novel with Chinese glosses, or a Hindi speaker a Spanish one with Hindi glosses. Chinese, Japanese, Korean, Arabic, and Hindi are available as gloss languages only, not yet as languages to learn.

What file formats can I upload?

PDF and EPUB, up to 100 MB per file. Books upload directly from your browser to Azure Blob Storage via a short-lived signed URL — the application server never sees the raw bytes in transit.

Yes. The free tier includes 2 books and 10 distinct pages of reading, with every feature unlocked (translation, audio narration, vocabulary games). Pro is $9.99 per month billed annually ($119.88 a year), $14.99 month-to-month, or a one-time $4.99 7-day pass, and raises the library to 100 books with unlimited pages. Annual plans are refundable in full within 30 days.

What is included in Pro?

Up to 100 books in your library, unlimited pages, AI-generated chapter summaries, and faster book processing. Pro lifts limits rather than gating features — translation, audio narration, and vocabulary practice are also fully available on the free plan.

Does Glossa work on mobile?

Yes, Glossa runs in any modern mobile browser. There is no native iOS or Android app yet; the responsive web app is the only way to use Glossa on phones today.

Is my uploaded content private?

Yes. Uploaded books are stored in a private Azure Blob container accessible only to your account, are never shared with other users, and are never used to train AI models. We do not sell user data.

How does Glossa decide which words to translate?

Glossa estimates how difficult each word in your book is for you, and only the words above your level get a translation written underneath — everything else stays as original text. It adjusts to your level automatically: the more you read and practise, the better it fits you. You can also set it yourself with a slider in the reader — a fuller slider shows more glosses, an emptier one fewer. The slider's stops carry CEFR labels (A1–C2) as a familiar reference point, not an official CEFR assessment.

How does the spaced-repetition vocabulary practice work?

Words you tap while reading are saved to your vocabulary list. Glossa surfaces them in short games — matching, fill-in-the-blank, multiple choice, parts-of-speech tagging, and sentence-scramble — scheduled so you re-encounter each word at increasing intervals based on how confidently you answered last time.

Is Glossa suitable for beginners?

Yes. Complete beginners can start in the phrasebook, the "My phrases" tab next to your books: you build a handful of sentences about your own life (who you are, your work, your family, why you're learning), each glossed word by word, read aloud, and practised until it comes without thinking. We think a few anchors like that make new vocabulary easier to build in a logical order, because every new word attaches to something you already know. Reading books works best once you can read simple sentences, roughly CEFR A2, though the reveal slider's lowest setting glosses nearly every word. Glossa is not a full course and does not teach grammar systematically, so some beginners will still want a course or textbook alongside it.

Does Glossa teach speaking?

Not directly. Glossa is a reading app. It supports listening and pronunciation: any sentence can be read aloud by a native-quality neural voice, for most languages the word card shows syllables and stress, and the phrasebook lets you build and drill sentences about yourself that you would actually say. But it has no speech recognition or conversation practice, so it cannot hear you speak. For speaking, pair it with a tutor, a conversation partner, or a speaking-focused app.

Can I use Glossa alongside ChatGPT or another AI assistant?

Yes. A general assistant is good at explaining a grammar point or a confusing passage on request; Glossa handles the reading itself, keeping a whole book readable at your level, glossing only the words above it, reading sentences aloud, and remembering the words you look up. On any plan, including free, you can also connect Glossa to Claude as a connector (MCP), so the assistant can see your library, reading activity, the words you keep missing and your phrasebook, and recommend books or build practice around them. It is read-only, except that, if you allow it, it can propose sentences for your phrasebook, which wait for you to keep or discard. It cannot change or delete anything else in your account. Connections from ChatGPT and Gemini are being worked on and not yet confirmed.

How is Glossa different from Duolingo?

Duolingo teaches with a fixed curriculum of synthetic exercises. Glossa is a reader: you upload real books you actually want to read, and translation and vocabulary practice are built around that content. For complete beginners, Glossa's first step is a phrasebook of sentences about your own life rather than a set course. Choose Duolingo for a structured course from zero; choose Glossa to start from sentences about yourself and move on to real books.

How is Glossa different from LingQ?

LingQ has a large catalog of curated lessons, a learner community, and native mobile apps, and it can import your own ebooks by splitting them into lessons. Glossa keeps your PDF or EPUB as one book and writes translations between the lines for only the words above your level, adjustable with a slider, where LingQ has you tap words to look them up. Choose LingQ for curated content and a phone app; choose Glossa to read a book you chose with glosses that adapt to you.

How is Glossa different from Readlang?

Both read your own books: Readlang takes DRM-free EPUB and plain text, and is strongest on web articles through its browser extension. Glossa also reads PDFs directly, and glosses only the words above your level, fewer as your vocabulary grows. Choose Readlang for web articles; choose Glossa for PDFs and whole books.

Can I import books from Project Gutenberg?

Yes. Glossa has a built-in browser for the Project Gutenberg catalog of public-domain titles. Pick a book in your target language and it imports in seconds without leaving the app.

What voices does Glossa use for audio narration?

Azure Neural Text-to-Speech voices, native-speaker quality in each supported language. Every user gets a default voice per language; additional voices can be unlocked using Glossa Points earned through reading.

Like Duolingo, but for reading books: the graduate path

A guide for the day the tree stops being enough. Disclosure: Glossa (our app) is one of the tools below. Competitor prices and features checked against each product’s official pages (linked under Sources) on 26 September 2026.

There’s a particular moment every long-streak Duolingo user knows: you open an actual book in the language — and bounce off it. It feels like failure. It isn’t. It’s the boundary of what any drill app can teach, and it arrives right on schedule. The good news: everything Duolingo did give you is exactly what reading needs to start — and the daily-streak habit you built is the hard part, already done.

What the drills gave you (a real foundation)

Give Duolingo its due. A finished (or even half-finished) course leaves you with a few thousand common words, the core grammar patterns, spelling-to-sound in your language, and — most underrated — a daily habit with years of momentum. That’s not nothing; that’s precisely the entry kit for reading. What drills can’t give you is the other half:

Sentences chosen to be exercises, not sentences chosen to say something. Real prose runs longer, subordinates clauses, and picks the surprising word — the things a drill format has to avoid.
Vocabulary breadth. Course apps concentrate on the most useful core vocabulary; reading research puts ordinary novels at around 8,000–9,000 word families for comfortable reading. That gap doesn’t close by repeating the tree — it closes by meeting words in volume, in context. Which is to say: by reading.
Stamina. Sixty seconds per exercise builds no tolerance for a page. Pages build tolerance for pages.

The jump, sized honestly

How far a finished course takes you depends on the course. Duolingo says its nine largest (English, Spanish, French, German, Italian, Portuguese, Japanese, Korean and Chinese) now teach through B2; smaller courses end earlier. Wherever yours ended, an adult novel is still a jump: per the coverage math a reader who recognises 85–90% of the words spends much of the effort on decoding, which makes unassisted novels hard going and assisted reading the practical next step. Three routes, in ascending order of ambition:

Graded readers — purpose-built books at your level; the classic on-ramp. What they’re great at and where they top out.
A real book you already know — the Harry Potter move; imported plot covers the missing coverage.
A real book with adaptive support — interlinear glosses under exactly the words a Duolingo-graduate vocabulary won’t have:

EnInunalugarplacedeoflatheMancha,Mancha,deofcuyowhosenombrenamenonotquieroI wantacordarme.to remember.

Don Quijote — Miguel de Cervantes, 1605. “In a place in La Mancha, whose name I do not wish to remember.” Drag the slider: right glosses everything, left glosses nothing. In the Glossa reader this adapts automatically to your level and to the words you already know.

Keep the streak, change the unit

The deepest thing Duolingo taught you wasn’t Spanish — it was showing up daily. Keep that, and change what a “day” is: from one lesson to 20 minutes of a book you actually want to finish. The psychology transfers cleanly; wanting to know what happens next is a stronger streak-keeper than any owl. (If you like the progress scaffolding, keep it — Glossa tracks streaks and pages quietly, and its vocabulary practice is built from the words you met in your book, which is spaced repetition with a plot.)

Apps like Duolingo, but for books

Short version — the full comparison lives in the nine-app roundup:

Glossa (ours) — upload any EPUB/PDF or pick a classic; adaptive interlinear glosses hold the book at readable coverage, with audio and review built in. Free for two books / 10 pages.
LingQ — the all-media ecosystem (books, video, podcasts) if you want one subscription for everything; expect a busy interface.
Readlang — the lean, cheap tap-to-translate web reader.
Beelinguapp — curated bilingual stories with narration; the gentlest first step, no own-book import.

Should you quit Duolingo?

Not necessarily — this isn’t an either/or. Drills are a fine warm-up and a good container for grammar review; many readers keep a five-minute tree habit alongside the book. The only mistake is expecting the tree to eventually become the book. It won’t; the book is the book. Duolingo got you to the trailhead — reading is the trail.

Free for 2 books and 10 pages of reading.

Sources

Official pages each competitor claim was checked against, on 26 September 2026. Prices change; if one of these disagrees with this page, trust the source and tell us at [email protected].

Duolingo — Courses that teach through B2 (blog, April 2026)
LingQ — Plans and pricing · Importing ebooks · Mobile apps · Languages
Readlang — Pricing · Features · PDF import (forum answer) · Voices (blog, May 2026)
Beelinguapp — App Store listing