This version is substantially revised and expanded from version 0.8.
The entire toolkit can be accessed via a single import statement
"import nltk", and there is a more convenient naming scheme. Calling
deprecated functions generates messages that help programmers update
their code. The corpus, tagger, and classifier modules have been
redesigned. All functionality of the old NLTK 1.4.3 is now covered by
NLTK-Lite 0.9. The book has been revised and expanded. A new data
package incorporates the existing corpus collection and contains new
sections for pre-specified grammars and pre-computed models. Several
new corpora have been added, including treebanks for Portuguese,
Spanish, Catalan and Dutch. A Macintosh distribution is provided.