The ISO Standard for Dialogue Act Annotation, Second Edition.

ISO standard 24617-2 for dialogue act annotation, established in 2012, has in the past few years been used both in corpus annotation and in the design and implementation of components of spoken and multimodal dialogue systems. This has brought some inaccuracies and undesirable limitations of the standard to light, which are addressed in the second edition. This second edition allows a more accurate annotation of dependence relations and rhetorical relations in dialogue. Moreover, a triple-layered plug-in mechanism is introduced which allows dialogue act descriptions to be enriched with information about their semantic content and other information, such as accompanying emotions, and which allows the annotation scheme to be customised by adding application-specific dialogue act types.