[Natural Language Processing with Python](http://www.nltk.org/book/)
## examples of usage
2020 [ Google and Facebook have both released new chatbots. Jiwei Li’s techniques are at the heart of both.](https://knowen-production.s3.amazonaws.com/uploads/attachment/file/4596/nlp%2Bchatbot.pdf)
[Leilani Battle - ForeCache, a tool designed to help researchers browse large arrays of data](https://www.technologyreview.com/innovator/leilani-battle/)