PyStemmer provides access to efficient algorithms for calculating a
"stemmed" form of a word. This is a form with most of the common
morphological endings removed; hopefully representing a common
linguistic base form. This is most useful in building search engines
and information retrieval software; for example, a search with stemming
enabled should be able to find a document containing "cycling" given the
query "cycles".

PyStemmer provides algorithms for several (mainly european) languages,
by wrapping the libstemmer library from the Snowball project in a Python
module. It also provides access to the classic Porter stemming algorithm
for english: although this has been superceded by an improved algorithm,
the original algorithm may be of interest to information retrieval
researchers wishing to reproduce results of earlier experiments.

WWW: http://pypi.python.org/pypi/PyStemmer/