Phrase Structure Annotation And Parsing For Learner English

There has been almost no work on phrase structure annotation and parsing specially designed for learner English despite the fact that they are useful for representing the structural characteristics of learner English. To address this problem, in this paper, we first propose a phrase structure annotation scheme for learner English and annotate two different learner corpora using it. Second, we show their usefulness, reporting on (a) inter-annotator agreement rate, (b) characteristic CFG rules in the corpora, and (c) parsing performance on them. In addition, we explore methods to improve phrase structure parsing for learner English (achieving an F-measure of 0.878). Finally, we release the full annotation guidelines, the annotated data, and the improved parser model for learner English to the public.