Semantic natural language processing - from texts to logical expressions? Universal knowledge base?
There are several implementations of semantic parsers that convert natural-language texts into formal logical representations of their meanings. Natural language understanding systems can also be based on discourse representation theories that represent the meanings of English texts using first-order logical predicates.

I have found at least one system that is able to generate a knowlege base from statements that are given in a natural language. The ACE Wiki is based on Attempto Controlled English, which is a semantically unambiguous subset of the English language.