During my first pass through the words of The Hobbit which are not in The Ten Thousand, I lemmatized about fifteen hundred as being inflected forms of words in The Ten Thousand.  We are left with seven thousand words to examine.  Tolkien invented many of these words, like “Thorin”  and “Mirkwood”.  Every author names his characters and locations, although the names may already be familiar to the readers, (“Spencer” and “Boston”), so these words don’t directly get at our question.  We will store them up safely in a separate sheet of my Great Spreadsheet of Doom and move on to our study of the non-naming yet non-common words.