Sources and licences

Wordü is possible thanks to these open data projects:

• Definitions, pronunciations, examples and translations from Wiktionary, extracted by Wiktextract (kaikki.org). Licensed CC BY-SA 4.0.

  https://kaikki.org/dictionary/English/

• Audio recordings from Wikimedia Commons, each under the licence shown on its page.

  https://commons.wikimedia.org/

• Vocabulary levels from The CEFR-J Wordlist Version 1.5 (compiled by Yukio Tono, Tokyo University of Foreign Studies; © Tono Laboratory, TUFS) and the Octanove Vocabulary Profile C1/C2 (CC BY-SA 4.0), distributed by Open Language Profiles.

  https://github.com/openlanguageprofiles/olp-en-cefrj

• Word frequency from FrequencyWords (Hermit Dave), built from OpenSubtitles. Licensed CC BY-SA 4.0.

  https://github.com/hermitdave/FrequencyWords

When a word isn't in those lists, its level is an estimate based on how often it is used.