The notion of genre has been widely explored using quantitative methods from both lexical and syntactical perspectives. However, discourse structure has rarely been used to examine genre. Mostly concerned with the interrelation of discourse units, discourse structure can play a crucial role in genre analysis. Nevertheless, few quantitative studies have explored genre distinctions from a discourse structure perspective. Here, we use two English discourse corpora (RST-DT and GUM) to investigate discourse structure from a novel viewpoint. The RST-DT is divided into four small subcorpora distinguished according to genre, and another corpus (GUM) containing seven genres are used for cross-verification. An RST (rhetorical structure theory) tree is converted into dependency representations by taking information from RST annotations to calculate the discourse distance through a process similar to that used to calculate syntactic dependency distance. Moreover, the data on dependency representations deriving from the two corpora are readily convertible into network data. Afterwards, we examine different genres in the two corpora by combining discourse distance and discourse network. The two methods are mutually complementary in comprehensively revealing the distinctiveness of various genres. Accordingly, we propose an effective quantitative method for assessing genre differences using discourse distance and discourse network. This quantitative study can help us better understand the nature of genre.
Switch-reference has been analyzed as a reference tracking mechanism, whose main function is to avoid ambiguity of reference. One domain where this function has been argued to manifest itself is referential choice. Kibrik (Kibrik, Andrej. 2011. Reference in discourse. Oxford: Oxford University Press) notably proposed that switch-reference marking plays the role of a referential aid, which helps to prevent referential conflict, thereby enabling the production of reduced referential expressions such as pronouns and zeros. The present study probes this theory through an analysis of the role of switch-reference marking in multifactorial models of referential choice in Mbyá Guaraní. We show that while switch-reference increases the likelihood of mention reduction in Mbyá Guaraní, this effect is marginal relative to other predictors of referential choice. We argue that this result is compatible with the analysis of switch-reference as a referential aid, but also supports analyses that emphasize the multiplicity of its functions, beyond the disambiguation of reference.