Devising a discourse error tagging system for an English learner corpus.

This paper reports on-going research aiming to result in the tagging of discourse errors in the Language Training and Teaching Center English Learner Corpus, a Taiwanese learner corpus of English constructed by the Graduate Institute of Linguistics and the Department of Foreign Languages and Literatures at National Taiwan University, the Department of English at National Chengchi University, and the LTTC, a language testing company. This study was motivated by the paucity of discourse error tags in other learner corpora (Diaz-Negrillo & Fernandez-Dominguez, 2006) and by a desire to examine discourse errors made by intermediate-level Taiwanese learners of English. In particular, this paper describes the pilot application of Rhetorical Structure Theory (RST) (Mann & Thompson, 1988) to the analysis of coherence relations in 45 written samples from the aforementioned corpus. This pilot study examines whether an RST coherence analysis can lead to tangible evidence for the existence of coherence breaks in the writing of the learners. The rationale of this study is that RST text analyses which violate some of the rules of RST diagram formation will point to coherence errors. This study is useful for the discourse error tagging of the corpus because after listing the RST diagram abnormalities which characterize each kind of coherence error, the discourse error tagging will be done in a principled way. Moreover, the frequency of coherence error types offers some preliminary indications about which error types warrant further investigation through the analysis of more writing samples. The ultimate goal of this investigation is to identify the location of the most frequent coherence error types, so that the corpus can be tagged for them. No validity and reliability tests have been conducted since this work was at an initial stage and only aimed to find out whether this method would be useful. Therefore, results are only preliminary. Results indicate that this approach can help locate coherence errors more reliably but that the tagger’s intuition is needed for some coherence errors and, of course, it is also needed whenever one “problem” in an RST diagram points to more than one possible coherence error.