Natural Language Toolkit (NLTK)

Treex - NLP Framework   (Compare Project)

Mostly written in Perl

License: artistic_gpl

Ruby LinkParser   (Compare Project)

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License: bsd

RelEx Semantic Relationship Extractor   (Compare Project)

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License: apache_2

Apache OpenNLP   (Compare Project)

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License: apache_2

Link Grammar   (Compare Project)

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License: lgpl21_or_later

CRM114 for Ruby   (Compare Project)

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License: mit

Affisix   (Compare Project)

License: gpl3

purepos   (Compare Project)

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License: lgpv3_or_later

MARF:Modular Audio Recognition Framework   (Compare Project)

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License: BSD-3-Clause

SimMetrics   (Compare Project)

Mostly written in Java

License: Unknown