Sources and Licenses

Last updated: 2026-10-28

The ready-made decks in the Kwipsy Library are built from open dictionaries, word lists and frequency data. This page credits those sources and states the license of the deck content. Cards and decks you create yourself are yours and are not covered by this page.

License of Library deck content

Several of the sources below are published under share-alike licenses. The content of Kwipsy Library decks — words, meanings, translations, levels and the other data in each card — is therefore made available under the Creative Commons Attribution-ShareAlike 4.0 International license (CC BY-SA 4.0). If you reuse it, credit Kwipsy and the sources below and share your adaptation under the same license.

The Kwipsy app itself, its design, code and the Kwipsy name and logo are not covered by this license.

Sources used in all languages

• Wiktionary, via wiktextract and kaikki.org — CC BY-SA. Meanings, parts of speech and translations. wiktionary.org
• wordfreq © Robyn Speer — data under CC BY-SA 4.0. Word frequencies. github.com/rspeer/wordfreq
• Open English WordNet — CC BY 4.0. github.com/globalwordnet/english-wordnet
• Princeton WordNet © Princeton University — used under the WordNet License.

English levels

• The CEFR-J Wordlist (Version 1.6), compiled by Yukio Tono, Tono Laboratory, Tokyo University of Foreign Studies — used to check the CEFR levels of English words, with acknowledgement as its terms require. cefr-j.org

Korean

• National Institute of Korean Language (국립국어원) — published under the Korea Open Government License, Type 1 (source attribution):
  • «현대 국어 사용 빈도 조사» (Frequency Survey of Modern Korean, 2002) and «현대 국어 사용 빈도 조사 2» (2005);
  • «한국어 학습용 어휘 목록» (Korean Learning Vocabulary List, 2003);
  • «2017년 국제 통용 한국어 표준 교육과정 적용 연구(4단계)» (International Standard Korean Curriculum, vocabulary and grammar grades, revised 2020-11-17) — the source of Korean levels.
  • korean.go.kr
• 한국어기초사전 (Basic Korean Dictionary), National Institute of Korean Language, 2019 XML export via spellcheck-ko — CC BY-SA 2.0 KR. Pronunciation audio from this dictionary is not used. krdict.korean.go.kr
• FrequencyWords by Hermit Dave, built from OpenSubtitles 2018 — CC BY-SA 4.0. github.com/hermitdave/FrequencyWords

Changes we make

We select and rank words, assign levels, group them into decks, write and edit example sentences, and translate and review the cards. These changes are part of the deck content and are shared under the same CC BY-SA 4.0 license.

Questions

If you are the author of a source and believe it is credited incorrectly, write to [email protected] and we will fix it.