These wordlists are extracts from Wikipedia. You can use them under the
terms of the GNU Free Documentation License. The processed data is

  - dewiki-20060123-pages-articles.xml
  - enwiki-20060125-pages-articles.xml

en-2 contains all words that match the regular expression

  [a-zA-Z0-9_\-\.\+\#\~\$\!\%\&]+

and occur twice. en-5 is a smaller subset that contains only words that
occure five time. de-2 and de-5 is almost the same for the German
export.