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We present an annotation effort that involves adding a new layer of annotation to an existing corpus. We are interested in how rhetorical relations are signalled in discourse, and thus begin with a corpus already annotated for rhetorical relations, to which we add signalling information. We show that a very large number of relations carry signals that identify them as such. The detailed, extensive analysis of signals in the corpus will aid research in the automatic parsing of discourse relations.

We present the RST Signalling Corpus (Das et al., 2015), a corpus annotated for signals of coherence relations. The corpus is developed over the RST Discourse Treebank (Carlson et al., 2002) which is annotated for coherence relations. In the RST Signalling Corpus, these relations are further annotated with signalling information. The corpus includes annotation not only for discourse markers which are considered to be the most typical (or sometimes the only type of) signals in discourse, but also for a wide array of other signals such as reference, lexical, semantic, syntactic, graphical and genre features as potential indicators of coherence relations. We describe the research underlying the development of the corpus and the annotation process, and provide details of the corpus. We also present the results of an inter-annotator agreement study, illustrating the validity and reproducibility of the annotation. The corpus is available through the Linguistic Data Consortium (LDC), and can be used to investigate the psycholinguistic mechanisms behind the interpretation of relations through signalling, and also to develop discourse-specific computational systems such as discourse parsing applications.

We present a new lexicon of English discourse connectives called DiMLex-Eng, built by merging information from two annotated corpora and an additional list of relation signals from the literature. The format follows the German connective lexicon DiMLex, which provides a crosslinguistically applicable XML schema. DiMLex-Eng contains 149 English connectives, and gives information on syntactic categories, discourse semantics and non-connective uses (if any). We report on the development steps and discuss design decisions encountered in the lexicon expansion phase. The resource is freely available for use in studies of discourse structure and computational applications.

We present a proposal to analyze disagreement in Rhetorical Structure Theory annotation which takes into account what we consider "legitimate" disagreements. In rhetorical analysis, as in many other pragmatic annotation tasks, a certain amount of disagreement is to be expected, and it is important to distinguish true mistakes from legitimate disagreements due to different possible interpretations of the structure and intention of a text. Using different sets of annotations in German and English, we present an analysis of such possible disagreements, and propose an underspecified representation that captures the disagreements.