Dictionary sources
A language model translates the words on the page. The dictionary the reader uses to choose which words to show in the other language, and from which level, and to take fallback translations from, is built from open sources:
- Wiktionary — word translations from the kaikki.org (Wiktextract), DBnary (Gilles Sérasset), WikDict and FreeDict dumps. Licence: CC BY-SA 3.0 and 4.0.
- ConceptNet 5 — word translations. Licence: CC BY-SA 4.0.
- wordfreq (Robyn Speer) — word frequencies for every language, used to sort words into the levels A1, A2 and B1. The frequencies include data from Google Books Ngrams, the Leeds Internet Corpus, Wikipedia, ParaCrawl and OpenSubtitles (opensubtitles.org). Licence: CC BY-SA 4.0.
The dictionary itself is open: ru-nl-cefr.json. You may use it under the licences of these sources.
“Двенадцать стульев” (The Twelve Chairs) by Ilya Ilf and Yevgeny Petrov — the text of the first edition (1928) from Russian Wikisource, public domain. “Il fu Mattia Pascal” by Luigi Pirandello (1904) and “Na srebrnym globie” by Jerzy Żuławski (1903) — texts from Italian and Polish Wikisource, public domain.