Usually a reference to the Stanford NLP parser but I have put in the link to the “The Stanford Natural Language Processing Group.”
From its webpage:
The Natural Language Processing Group at Stanford University is a team of faculty, research scientists, postdocs, programmers and students who work together on algorithms that allow computers to process and understand human languages. Our work ranges from basic research in computational linguistics to key applications in human language technology, and covers areas such as sentence understanding, machine translation, probabilistic parsing and tagging, biomedical information extraction, grammar induction, word sense disambiguation, and automatic question answering.
A distinguishing feature of the Stanford NLP Group is our effective combination of sophisticated and deep linguistic modeling and data analysis with innovative probabilistic and machine learning approaches to NLP. Our research has resulted in state-of-the-art technology for robust, broad-coverage natural-language processing in many languages. These technologies include our part-of-speech tagger, which currently has the best published performance in the world; a high performance probabilistic parser; a competition-winning biological named entity recognition system; and algorithms for processing Arabic, Chinese, and German text.
Quick link to Stanford NLP Software page.