CEFR-J English Profiles (Open Language Profiles)

The CEFR-J English Profiles, published as the Open Language Profiles English datasets, map English vocabulary and grammar to fine-grained CEFR-J sub-levels. They were built by Tono Laboratory at Tokyo University of Foreign Studies (TUFS), led by Yukio Tono, who adapted the Common European Framework of Reference into a finer scale better suited to learners in Japan and comparable settings. Three datasets travel together: the CEFR-J Vocabulary Profile (version 1.5 on GitHub, version 1.6 on the official site, roughly 7,801 items spanning A1 to B2), a CEFR-J Grammar Profile of grammatical items tagged by level, and the Octanove Vocabulary Profile covering the advanced C1 and C2 range.

You can access the material two ways. The official download page at cefr-j.org offers ZIP archives, Excel workbooks and PDFs, and bundles a text profiler (CVLA) that scores a passage for difficulty. The openlanguageprofiles GitHub repository publishes the same profiles as plain CSV, which is the easiest form to load into a pipeline. Everything is small, so the whole set fits comfortably in memory.

For RAG the profiles act as a controlled vocabulary and a difficulty index: each row is a word or structure with a level tag, so you can attach a CEFR band to any English text and retrieve items by level. For an AI English tutor the value is more direct. The wordlist and grammar profile let you sequence teaching by level, generate practice items pitched to a learner's band, gauge whether a reading passage sits above or below a target, and model mastery against a recognised progression. It complements the standards frameworks we list, such as Common Core and NGSS, but where those describe subject competencies, CEFR-J describes English proficiency itself.

On licensing, read carefully. The core CEFR-J data is free for research and commercial use provided you cite it properly (copyright Tono Laboratory, TUFS). The bundled Octanove C1/C2 profile differs: it is released under Creative Commons Attribution-ShareAlike 4.0, so reusing that file carries a share-alike obligation. Attribution is required throughout.