Lexical correlates of comprehensibility versus accentedness in second language speech*

The current project investigated the extent to which several lexical aspects of second language (L2) speech – appropriateness, fluency, variation, sophistication, abstractness, sense relations – interact to influence native speakers’ judgements of comprehensibility (ease of understanding) and accentedness (linguistic nativelikeness). Extemporaneous speech elicited from 40 French speakers of English with varied L2 proficiency levels was first evaluated by 10 native-speaking raters for comprehensibility and accentedness. Subsequently, the dataset was transcribed and analyzed for 12 lexical factors. Various lexical properties of L2 speech were found to be associated with L2 comprehensibility, and especially lexical accuracy (lemma appropriateness) and complexity (polysemy), indicating that these lexical variables are associated with successful L2 communication. In contrast, native speakers’ accent judgements seemed to be linked to surface-level details of lexical content (abstractness) and form (variation, morphological accuracy) rather than to its conceptual and contextual details (e.g., lemma appropriateness, polysemy).