The Living Archives
The linguistic data comes from kaikki.org (kaikki — [Finnish] all, everything, everyone), a digital archive and data mining group who have extracted millions of words, and the information about those words, from Wiktionary.
Wiktionary is a free, collaborative, multilingual online dictionary which aims to describe all words of all languages using definitions and descriptions in English. Wiktionary is written by volunteer editors and hosted by the Wikimedia Foundation.