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 18 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 18 languages: English, Spanish, French, German, Italian, Portuguese, Dutch, Swedish, Norwegian, Danish, Polish, Russian, Ukrainian, Arabic, Chinese (Simplified), Japanese, Korean, and Hindi. Coverage depends on available CEFR data; languages without curated CEFR lists fall back to a machine-learning difficulty classifier.
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 $14.99 per month or a one-time $4.99 7-day pass, and removes the book and page limits.
What is included in Pro?
Unlimited books, unlimited pages, AI-generated chapter summaries, and faster book processing. Pro removes 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.
What is CEFR scoring and how does Glossa use it?
CEFR is the Common European Framework of Reference for Languages, a six-level scale from A1 (absolute beginner) to C2 (near-native). Glossa scores every word in your book on this scale and a difficulty slider in the reader controls which words get translated inline — lower slider shows more glosses for harder words, higher slider shows fewer glosses and more original text.
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.
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. Duolingo suits absolute beginners; Glossa suits learners who can read elementary sentences and want to engage with longer material.
How is Glossa different from LingQ?
LingQ has a built-in catalog of curated lessons and a learner community. Glossa lets you upload any PDF or EPUB and adds CEFR-adaptive interlinear translation, which LingQ does not offer. LingQ has more pre-curated content; Glossa gives you more control over what you read.
How is Glossa different from Readlang?
Readlang is primarily a browser extension for translating words in web articles. Glossa is book-centric — built around uploading PDFs and EPUBs, with audio narration, CEFR-adaptive glossing, and structured vocabulary games. Choose Readlang for web articles; choose Glossa for full 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.