Frequently asked questions
About Glossa — what it does, what it costs, and how it compares to other language-learning tools.
What is Glossa?
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.
Is Glossa free?
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.
Still have questions?
Email [email protected] and we will get back to you. For account-specific issues you can also use the in-app feedback form once signed in.