NLTK: The Natural Language Toolkit

The Natural Language Toolkit (NLTK) is a suite of program modules, data sets, and tutorials designed to support both research and teaching in computational linguistics and natural language processing. It is implemented in Python and distributed under the GPL open-source license, making it freely available to the community. Over the year preceding the paper, the toolkit was substantially rewritten, simplifying many of its linguistic data structures and taking advantage of recent enhancements in the Python language.

The paper reports on this simplified version of the toolkit and explains how it is used in teaching NLP. By packaging reusable components alongside datasets and instructional material in an accessible language, NLTK lowered the barrier to hands-on natural language processing for students and researchers. It became one of the most widely adopted open-source platforms for NLP education and prototyping.