The Stanford Natural Language Processing GroupQuoted::
The Stanford NLP group makes a number of NLP-related tools available for public release:
The Stanford Parser
Java implementations of probabilistic natural language parsers, both highly optimized PCFG and dependency parsers, and a lexicalized PCFG parser. Including: Parser FAQ and Online parser demo.
The Stanford POS Tagger
A Java implementation of a maximum-entropy part-of-speech (POS) tagger
The Stanford Classifier
A Java implementation of conditional loglinear model classification (a.k.a., maximum entropy models)
Tregex
A Java implementation of a Tgrep2-style utility for matching patterns in trees.
Tsurgeon
A tree-transformation utility built on top of Tregex in Java.
FrameNet II Reader software
Support files for reading FrameNet II XML files into Java data structures.
All Stanford NLP Group software distributions are licensed under the GNU Public License. (Note that this is the full GPL, which allows its use for research purposes or other free software projects but does not allow its incorporation into any type of commercial software, even in part or in translation.)
All our software is written in Java, and the most recent distributions require JDK 1.5+ (some of the older ones run on JDK 1.4). Distribution packages include components for command-line invocation, a Java API, and source code.