I am searching for information on algorithms to process text sentences or to follow a structure when creating sentences that are valid in a normal human language such as English
Writing random sentences is not that hard. Any parser textbook's simple-english-grammar example can be run in reverse to generate grammatically correct nonsense sentences.
Another way is the word-tuple-random-walk, made popular by the old BYTE magazine TRAVESTY, or stuff like http://www.perlmonks.org/index.pl?node_id=94856