chatter is a collection of simple Natural Language
Processing algorithms.
Chatter supports:
Part of speech tagging with Averaged
Perceptrons. Based on the Python implementation
by Matthew Honnibal:
(http://honnibal.wordpress.com/2013/09/11/a-good-part-of-speechpos-tagger-in-about-200-lines-of-python/) See NLP.POS for the details of part-of-speech tagging with chatter.
Phrasal Chunking (also with an Averaged Perceptron) to identify arbitrary chunks based on training data.
Document similarity; A cosine-based similarity measure, and TF-IDF calculations,
are available in the NLP.Similarity.VectorSim module.
Information Extraction patterns via (http://www.haskell.org/haskellwiki/Parsec/) Parsec
Chatter comes with models for POS tagging and
Phrasal Chunking that have been trained on the
Brown corpus (POS only) and the Conll2000 corpus
(POS and Chunking)