Natural Language Toolkit
Original author(s)Steven Bird, Edward Loper, Ewan Klein
Developer(s)Team NLTK
Initial release2001; 23 years ago (2001)[1]
Stable release
3.8.1[2] Edit this on Wikidata / 2 January 2023; 17 months ago (2 January 2023)
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 supports classification, tokenization, stemming, tagging, parsing, and semantic reasoning functionalities.[4] It was developed by Steven Bird and Edward Loper in the Department of Computer and Information Science at the University of Pennsylvania.[5] 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,[6] plus a cookbook.[7]

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.[8] 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.

Library highlights

See also


  1. ^ "Project site on SourceForge". 9 July 2001.
  2. ^ "Release 3.8.1". 2 January 2023. Retrieved 27 April 2023.
  3. ^ "NLTK License". NLTK Project. Retrieved 14 February 2015.
  4. ^ "NLTK Courses". Google Docs. Retrieved 15 June 2016.
  5. ^ "Preface". Retrieved 15 June 2016.
  6. ^ Bird, Steven; Klein, Ewan; Loper, Edward (2009). Natural Language Processing with Python. O'Reilly Media Inc. ISBN 978-0-596-51649-9.
  7. ^ Perkins, Jacob (2010). Python Text Processing with NLTK 2.0 Cookbook. Packt Publishing. ISBN 978-1849513609.
  8. ^ 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)): Cite journal requires |journal= (help)
  9. ^ "NLTK :: Sample usage for drt". Retrieved 14 July 2022.