A word tree depicts multiple parallel sequences of words. It could be used to show which words most often follow or precede a target word (e.g., "Cats are...") or to show a hierarchy of terms (e.g., a decision tree).
Google word trees are able to process large amounts of text quickly. Modern systems should be able to handle novel-sized amounts of text without significant delay.
https://developers.google.com/chart/interactive/docs/gallery/wordtree
