Natural Language Toolkit

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Natural Language Toolkit
Original author(s)Steven Bird, Edward Loper, Ewan Klein
Developer(s)Team NLTK
Initial release2001; 20 years ago (2001)[1]
Stable release
3.6.1 / 7 April 2021; 6 months ago (2021-04-07)[2]
Written inPython
TypeNatural language processing
LicenseApache 2.0[3]
Parse tree generated with NLTK

The Natural Language Toolkit, or more commonly NLTK, is a suite of libraries and programs for symbolic and statistical natural language processing (NLP) for English written in the Python programming language. It was developed by Steven Bird and Edward Loper in the Department of Computer and Information Science at the University of Pennsylvania.[4] NLTK includes graphical demonstrations and sample data. It is accompanied by a book that explains the underlying concepts behind the language processing tasks supported by the toolkit,[5] plus a cookbook.[6]

NLTK is intended to support research and teaching in NLP or closely related areas, including empirical linguistics, cognitive science, artificial intelligence, information retrieval, and machine learning.[7] NLTK has been used successfully as a teaching tool, as an individual study tool, and as a platform for prototyping and building research systems. There are 32 universities in the US and 25 countries using NLTK in their courses. NLTK supports classification, tokenization, stemming, tagging, parsing, and semantic reasoning functionalities.[8]

Library highlights[edit]

See also[edit]


  1. ^ "Project site on SourceForge". 9 July 2001.
  2. ^ "NLTK ChangeLog". Retrieved 13 April 2021.
  3. ^ "NLTK License". NLTK Project. Retrieved 14 February 2015.
  4. ^ "Preface". Retrieved 15 June 2016.
  5. ^ Bird, Steven; Klein, Ewan; Loper, Edward (2009). Natural Language Processing with Python. O'Reilly Media Inc. ISBN 978-0-596-51649-9.
  6. ^ Perkins, Jacob (2010). Python Text Processing with NLTK 2.0 Cookbook. Packt Publishing. ISBN 978-1849513609.
  7. ^ Bird, Steven; Klein, Ewan; Loper, Edward; Baldridge, Jason (2008). "Multidisciplinary instruction with the Natural Language Toolkit" (PDF). Proceedings of the Third Workshop on Issues in Teaching Computational Linguistics, ACL. Archived from the original (PDF) on 2 September 2011. Cite journal requires |journal= (help)
  8. ^ "NLTK Courses". Google Docs. Retrieved 15 June 2016.

External links[edit]