Current state-of-the-art statistical parsers ( Collins 1999 ; Charniak 2000 ) are all trained on large annotated corpora such as the Penn Treebank ( Marcus , Santorini , and Marcinkiewicz 1993 ) .
headdriven statistical models for natural language parsing
Michael Collins
For example , while it is difficult to induce a grammar with raw text alone , the task is tractable when the syntactic analysis for each sentence is provided as a part of the training data ( Pereira and Schabes 1992 ) . Current state-of-the-art statistical parsers ( Collins 1999 ; Charniak 2000 ) are all trained on large annotated corpora such as the Penn Treebank ( Marcus , Santorini , and Marcinkiewicz 1993 ) . However , supervised training data are difficult to obtain ; existing corpora might not contain the relevant type of annotation , and the data might not be in the domain of interest .
Current state-of-the-art statistical parsers ( @@CITATION ; Charniak 2000 ) are all trained on large annotated corpora such as the Penn Treebank ( Marcus , Santorini , and Marcinkiewicz 1993 ) .