Abstract
<p>Prompted monologues – where people speak at length in response to a topic prompt – offer a controlled but ecologically valid way to study discourse production. However, there is little systematic understanding of how speaker characteristics, topic properties, and experimental context influence discourse of this kind. The Edinburgh Discourse Corpus (EDC) addresses these limitations, bringing together 7,261 spoken monologues collected across nine studies varying in experimental settings, instructions, and task demands. Participants produced speech for between 50 and 90s at a time, in response to a diverse set of prompts probing knowledge and opinions about a range of topics. The corpus contains responses from 462 participants and comprises over a million words of transcribed speech. We calculated 23 measures that capture lexical, semantic, syntactic and discourse-level properties and used Principal Components Analysis to reduce these to seven interpretable components. These speech components were shaped by characteristics of the speaker, prompt, and experimental context. Older adults exhibited reduced speech coherence, positivity, and emotional intensity, but also drew on a more sophisticated vocabulary. Structured prompts elicited more lexically-constrained content while unstructured, open-ended prompts elicited more emotionally-charged language. Experimental context, including setting, task demands, and instruction types, also affected speech, highlighting the role of contextual and pragmatic factors on discourse. These findings suggest that discourse properties are sensitive to a wide range of speaker, prompt and contextual influences, with implications for the design of future discourse elicitation studies. The full EDC, including all transcripts and speech measures, is available as an open-access resource.</p>