(This web page is permanently under construction.) Penn Treebank Project

The Penn Treebank Project

[picture of pine trees and mountains] The Penn Treebank Project annotates naturally-occuring text for linguistic structure. Most notably, we produce skeletal parses showing rough syntactic and semantic information -- a bank of linguistic trees. We also annotate text with part-of-speech tags, and for the Switchboard corpus of telephone conversations, dysfluency annotation. We are located in the LINC Laboratory of the Computer and Information Science Department at the University of Pennsylvania.
All data produced by the Treebank is released through the Linguistic Data Consortium.

Descriptions and samples of annotated corpora:

Wall Street Journal | The Brown Corpus | Switchboard | ATIS

On-line tgrep searches are now possible for those with LDC Online access.

Frequently Asked Questions (FAQs)

  • tokenization
  • NP heads and Base NPs in Treebank II bracketing

    Annotation Style Manuals

  • Part-of-speech tagging
  • Treebank I bracketing was used until 12/92.
  • Treebank II bracketing is designed to allow the extraction of simple predicate-argument structure.
  • Dysfluency annotation used for Switchboard corpus only

    [image of CD] Treebank Releases on CD

  • Preliminary Release, Version 0.5 CDROM, 1992
  • Release 2 CDROM, 1995


  • A nice overview of the project (before Treebank II style), Computational Linguistics, vol. 19, 1993.
  • Introduction to predicate-argument bracketing (a.k.a. Treebank II), ARPA '94.


    Principal Investigator:
    Mitchell Marcus
    Project Administrator:
    Ann Taylor
    Programmer/Data Manager:
    Robert MacIntyre
    Ann Bies, Constance Cooper, Mark Ferguson, Alyson Littman

    Links to other sites

  • AMALGAM Project (Automatic Mapping Among Lexico-Grammatical Annotation Model)
  • CCALAS (Centre for Computer Analysis of Language and Speech)
  • The LDC's Linguistic Annotation Page Tools and formats for creating linguistic annotations.
    This web page is maintained by treebank@unagi.cis.upenn.edu.
    Last change: $Date: 1999/02/02 17:57:13 $ UTC.
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