The Klingon language is apparently copyrighted by Paramount Studios. The nonprofit Klingon Language Institute does not distribute any kind of canonical Klingon-English dictionary, because it fears litigation from Star Trek's parent company.
But the problem is, the Klingon language belongs to Paramount; it's copyrighted. If someone started distributing lists of Klingon words (or descriptions of grammar, etc.), then Paramount might view this as competition for the legitimate sale of their own products, which would be A Bad Thing.
Besides, the very act of compiling your own list, even if it's just from TKD , can be extremely educational