Maximum entropy is a powerful method for constructing statistical models of classification tasks, such as part-of-speech tagging in Natural Language Processing. The Quipu Maximum Entropy Package is a Java implementation of the maximum entropy framework. It allows you to train, evaluate, and use maxent models.
Grok is a library of Java components for performing various natural language tasks. These include several preprocessing tasks, chart parsing, a large categorial grammar for English (induced from the Penn treebank), and some knowledge representation components (basic coreference, salience tracking, etc.). The library also has a companion kit which provides a GUI interface to the components, several of which are implementations of interfaces in the Quipu OpenNLP API.
Linguaphile is a simple command line language translator. It is open source, platform independent, and programmed in Perl. Linguaphile currently supports the following languages: Afrikaans, Alawa, Albanian, Arrernte, Basque, Belarusian, Bulgarian, Catalan, Croatian, Czech, Danish, Dutch, English, Esperanto, Estonian, Finnish, French, Galician, German, Greek, Hawaiian, Hungarian, Icelandic, Indonesian, Interlingua, Irish, Italian, Kala Lagaw Ya, Korean, Kriol, Latvian, Lithuanian, Malay, Maltese, Maori, Norwegian, Pitjantjatjara, Polish, Portuguese, Romanian, Russian, Samoan, Serbian, Slovak, Slovenian, Spanish, Swahili, Swedish, Thai, Tok Pisin, Turkish, Ukrainian, Warlpiri, and Welsh. The Spanish to English translation is the most useful at this stage.
Ciao is a complete Prolog system subsuming ISO-Prolog with a novel modular design which allows both restricting and extending the language. Ciao extensions currently include feature terms (records), higher-order, functions, constraints, objects, persistent predicates, a good base for distributed execution (agents), and concurrency. Libraries also support WWW programming, sockets, and external interfaces (C, Java, TCL/Tk, relational databases, etc.). An Emacs-based environment, a stand-alone compiler, and a toplevel shell are also provided.