Parsing is the task of analyzing the grammatical structure of natural language. Given a sequence of words, a parser forms units like subject, verb, object and determines the relations between these units according to some grammar formalism. Our work has focused on learning probabilistic context-free grammars (PCFGs) which assign a sequence of words the most likely parse tree. The parser supports a variety of languages and achieves state-of-the-art performance on most of them. For additional information and related projects visit the Berkeley NLP website.