Credits
Last updated 31 October 2026
SLM's word lists and sentences are built from open resources made by many people. Thank you to everyone who writes and checks them.
Language data
- CC-CEDICT: Chinese readings and English meanings. Licence: CC BY-SA 4.0.
- HSK 3.0 word and character lists (GF 0025-2021), via ivankra/hsk30: Official HSK levels for Chinese words and characters. Licence: MIT (list from a PRC Ministry of Education standard).
- jieba word frequencies: How common Chinese words are. Licence: MIT.
- Wiktionary, via kaikki.org (Wiktextract): English meanings, pronunciation (IPA), gender and word forms for Spanish and French; tone-marked spellings and meanings for Yoruba. Licence: CC BY-SA 4.0 and GFDL.
- CEFRLex: ELELex (Spanish) and FLELex (French), CENTAL, UCLouvain: CEFR levels of words as used in learner textbooks. Licence: CC BY-NC-SA 4.0 (non-commercial).
- OpenSubtitles 2018 frequency lists, by Hermit Dave: How common English, Spanish, French and Japanese words are in real speech. Licence: MIT.
- JMdict, Electronic Dictionary Research and Development Group: Japanese readings and English meanings. Licence: CC BY-SA 4.0.
- JLPT vocabulary lists, by Jonathan Waller (tanos.co.uk): JLPT N5 to N1 levels for Japanese words. Licence: CC BY.
- MENYO-20k, by David Adelani and others (Masakhane): Yoruba sentences with English translations, and how often Yoruba words are used. Licence: CC BY-NC 4.0 (non-commercial).
- Open English WordNet 2025, Global WordNet Association (based on Princeton WordNet): English definitions for words, phrases and idioms. Licence: CC BY 4.0.
- Princeton WordNet 3.1, Princeton University: How often each English meaning is used, to show the everyday meaning first. Licence: WordNet 3.0 licence (free use with this notice).
- SS4 English vocabulary list, by the SLM team: The core English word list (with WordNet for the letters it doesn't cover yet). Licence: SLM.
- Tatoeba: Example sentences with English translations, used in sentence puzzles. Licence: CC BY 2.0 FR. Each sentence belongs to its Tatoeba contributor..
How SLM uses them
SLM selects, cleans and levels the data (for example, choosing a learner-friendly meaning and placing each word at a level). Those built word lists are shared under the same licences as their sources. Where a level is estimated rather than taken from an official list, the app says so.