https://wordnet.princeton.edu/WordNet® is a large lexical database of English. Nouns, verbs, adjectives and adverbs are grouped into sets of cognitive synonyms (synsets), each expressing a distinct concept.
Although it is downloadable, I don't think it could be useful this way, because it links to zero translation.
But it could help to take inspiration on their semantic field for a concept, and in the far future, it may help to find new concepts to add to Panlexia.
Example with a search on "soya":
http://wordnetweb.princeton.edu/perl/we ... o3=&o4=&h=
http://wordnetweb.princeton.edu/perl/we ... =00&s=soya
Warning: it's very slow. That will be the good reason to download it