  Understanding and visualizing human discourse has long being a challenging
task. Although recent work on argument mining have shown success in classifying
the role of various sentences, the task of recognizing concepts and
understanding the ways in which they are discussed remains challenging. Given
an email thread or a transcript of a group discussion, our task is to extract
the relevant concepts and understand how they are referenced and re-referenced
throughout the discussion. In the present work, we present a preliminary
approach for extracting and visualizing group discourse by adapting Wikipedia's
category hierarchy to be an external concept ontology. From a user study, we
found that our method achieved better results than 4 strong alternative
approaches, and we illustrate our visualization method based on the extracted
discourse flows.
