Credits
The open word lists behind IAspid's vocabulary levels
IAspid decides the level of each word you say from four open lists. We cite them here, as their licenses ask, and thank their authors.
Important: The levels in IAspid are adapted from these lists: word forms are grouped under their base word, and the lists are combined. They are not the original datasets.
CEFR-J Wordlist 1.5
Words from A1 to B2, with their CEFR level.
The CEFR-J Wordlist Version 1.5. Compiled by Yukio Tono, Tokyo University of Foreign Studies. The copyright belongs to Tono Laboratory at TUFS. Distributed by Open Language Profiles.
Octanove Vocabulary Profile C1/C2
Words at C1 and C2, with their CEFR level.
Octanove Vocabulary Profile C1/C2, version 1.0, by Octanove Labs, licensed under CC BY-SA 4.0. Distributed by Open Language Profiles.
SUBTLEX-US
Estimates the level of the words the lists above do not have, from how often they appear in American film and TV subtitles. Levels estimated this way are shown with a tilde, like ~B2.
Brysbaert, M., & New, B. (2009). Moving beyond Kučera and Francis: A critical evaluation of current word frequency norms and the introduction of a new and improved word frequency measure for American English. Behavior Research Methods, 41(4), 977–990.
British spellings
Pairs British spellings with American ones, so realise and realize count as the same word.
From the American-British English Translator by hyperreality, MIT License.