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Natural Language Toolkit (NLTK)
Authors: Steven Bird <>
Edward Loper <>
Ewan Klein <>
Copyright (C) 2001-2012 NLTK Project
For license information, see LICENSE.txt
NLTK -- the Natural Language Toolkit -- is a suite of open source
Python modules, data sets and tutorials supporting research and
development in Natural Language Processing.
Documentation: A substantial amount of documentation about how
to use NLTK, including a textbook and API documention, is
available from the NLTK website:
- 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.
Mailing Lists: There are several mailing lists associated with NLTK:
- nltk: Public information and announcements about NLTK (very low volume)
- nltk-users: Discussions amongst NLTK users
- nltk-dev: Discussions amongst NLTK developers
- nltk-translation: Discussions about translating the NLTK book
- nltk-commits: Subversion commit logs for NLTK
Contributing: If you would like to contribute to NLTK,
please see
Donating: Have you found the toolkit helpful? Please support NLTK development
by donating to the project via PayPal, using the link on the NLTK homepage.
Redistributing: NLTK source code is distributed under the Apache 2.0 License.
NLTK documentation is distributed under the Creative Commons
Attribution-Noncommercial-No Derivative Works 3.0 United States license.
NLTK corpora are provided under the terms given in the README file
for each corpus; all are redistributable, and available for non-commercial use.
NLTK may be freely redistributed, subject to the provisions of these licenses.
Citing: If you publish work that uses NLTK, please cite the NLTK book, as follows:
Bird, Steven, Edward Loper and Ewan Klein (2009).
Natural Language Processing with Python. O'Reilly Media Inc.
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