A recent consensus on a task-oriented level of semantic representation to be layered on top of the existing Penn Treebank syntactic structures has been achieved. This level, know as the Proposition Bank, or PropBank, consists of argument labels for the semantic roles of individual verbs and similar predicating expressions such as participial modifiers and nominalizations. This talk will describe the PropBank verb semantic role annotation being done at Penn for both English and Chinese. The annotation process will be discussed as well as the use of existing lexical resources such as WordNet, Levin classes and VerbNet. Similar projects include the FrameNet Project at Berkeley and the Prague Tectogrammatics project. PropBank annotation is shallower than the Prague Tectogrammatics project and more broad coverage than FrameNet, in that every verb instance in the corpus has to be annotated.
The talk will also briefly describe progress in developing automatic semantic role labelers based on this training data and investigations into the role of sense distinctions in improving performance.