NLP – Natural Language Processing
NLU – Natural Language Understanding
[Wikipedia] – has tons of resources about NLP
[Microsoft] – has a special group dedicated to NLP
[SourceForge] – has source code to several open source NLP projects
[Ai-depot] – has an interesting article on using Morphology, Syntax, Semantics, and Pragmatics to perform NLP
[Dogpile] – has more natural language processing results
[SourceForge] – has more open source projects related to NLU
[Dogpile] – has more natural language understanding results
[Gate] – General Architecture for Text Engineering is a widely used and extensive Java library for NLP