NLTK

说明：  本书本源于国外大学课堂上的讲义，但是由于其配有相应的运行环境，获得了很好的教学效果，后编写为书。该书主要用于中文信息处理领域，对信息处理的各个子问题都进行了深入的讲解。
(The book covers a wide range of introductory topics in NLP, and shows how to do all the processing tasks using the toolkit. The toolkit s reference documentation describes every module,interface, class, method, function, and variable in the toolkit This documentation should be useful to both users and developers. )