classical greek and latin word frequencies: http://kyle-p-johnson.com/blog/2015/04/23/most-common-greek-latin-words.html
english word frequencies: project gutenberg
word frequencies from subtitles: https://github.com/hermitdave/FrequencyWords/tree/master/content/2016
english wiktionary dump from: https://dumps.wikimedia.org/enwiktionary/latest/