GrAF: A Graph-based Format for Linguistic Annotations

In this paper we describe the Graph Annotation Format (GrAF) and show how it is used represent not only independent linguistic annotations, but also sets of merged annotations as a single graph. To demonstrate this, we have automatically transduced several different annotations of the Wall Street Journal corpus into GrAF and show how the annotations can then be merged, analyzed, and visualized using standard graph algorithms and tools. We also discuss how, as a standard graph representation, it allows for the application of well-established graph traversal and analysis algorithms to produce information about interactions and commonalities among merged annotations. GrAF is an extension of the Linguistic Annotation Framework (LAF) (Ide and Romary, 2004, 2006) developed within ISO TC37 SC4 and as such, implements state-of-the-art best practice guidelines for representing linguistic annotations.