Many people have contributed to NLTK:

Project Leaders: Steven Bird, Edward Loper, Ewan Klein

These people manage the code repository and website, and oversee the strategic direction of the project. They are listed as "Project Owners" on this site.

Package Maintainers: Greg Aumann (toolbox), Steven Bethard (wordnet), Dan Garrette (inference, sem), Peter Ljunglöf (parse), Bjørn Arild Mæland (testing), Joel Nothman (metrics)

These people are responsible for maintaining specific modules; new issues relating to a module are assigned to them by default; if they stop maintaining the module it simply reverts to the NLTK developers as a group.

Project Members: Greg Aumann, Steven Bethard, Jordan Boyd-Graber, Lucas Cooper, Dan Garrette, Sumukh Ghodke, Peter Ljunglöf, Tom Lippincott, Nitin Madnani, Bjørn Mæland, Jason Narad, Joel Nothman, Jacob Perkins, Alex Rudnick, Brandon Rhodes, Richard Sproat

These people contribute to specific initiatives, as agreed with the project leaders; typically they maintain code in nltk_contrib or contribute documentation, or help with packaging. They have commit access to the NLTK source repository.

Contributors: Rami Al-Rfou', Greg Aumann, Paul Bedaride, Steven Bethard, Robert Berwick, Nathan Bodenstab, Francis Bond, Paul Bone, Daniel Blanchard, Phil Blunsom, Steve Cassidy, Chen-Fu Chiang, Dmitry Chichkov, Jinyoung Choi, Andrew Clausen, Lucas Champollion, Trevor Cohn, Chris Crowner, James Curran, Dariel Dato-on, Selina Dennis, Leon Derczynski, Alexis Dimitriadis, Nikhil Dinesh, Liang Dong, Rebecca Dridan, Dan Garrette, Jean Mark Gawron, Sumukh Ghodke, Yoav Goldberg, Brent Gray, Eduardo Pereira Habkost, Masato Hagiwara, Yurie Hara, Will Hardy, Peter Hawkins, Michael Heilman, Amy Holland, Kristy Hollingshead, Baden Hughes, Edward Ivanovic, Thomas Jakobsen, Piotr Kasprzyk, Chris Koenig, Haejoong Lee, Tom Lippincott, Peter Ljunglöf, Nitin Madnani, Christopher Maloof, Rob Malouf, Iker Manterola, Carl de Marcken, Mitch Marcus, Torsten Marek, Robert Marshall, Xinfan Meng, Margaret Mitchell, Tomonori Nagano, Jason Narad, Eric Nichols, Joel Nothman, Jacob Perkins, Alberto Planas, Martin Thorsen Ranang, Joshua Ritterman, Stuart Robinson, Carlos Rodriguez, Jussi Salmela, Geoffrey Sampson, Kepa Sarasola, Kevin Scannell, Thomas Skardal, Eric Smith, Rob Speer, Peter Spiller, Peter Stahl, Oliver Steele, Jan Strunk, Claire Taylor, Steven Tomcavage, Tiago Tresoldi, Petro Verkhogliad, Peter Wang, Charlotte Wilson, Beracah Yankama, Patrick Ye.

These people have contributed source code or documentation to NLTK.