Direct and indirect speech in aphasia: studies of spoken discourse production and comprehension

Speakers with aphasia (a language impairment due to acquired brain damage) have difficulty processing grammatically complex sentences. In this dissertation we study the processing of direct speech constructions (e.g., John said: “I have to leave”) by people with and without aphasia.

First, we study how often and in which ways speakers with aphasia produce direct speech constructions. Comparing the results to those of a control group, we find that people with aphasia produce more direct speech constructions than “healthy” speakers. Furthermore, depending on their aphasia type, individuals with aphasia use different forms of direct speech constructions. The larger proportion and adapted use of direct speech by individuals with aphasia is suggested to be an adaptation strategy to get around specific linguistic impairments.

Now that we know that speakers with aphasia produce relatively many direct speech constructions, the question arises what their effects are one the listener. It has often been claimed that direct speech contributes to liveliness, and that liveliness contributes to comprehensibility. Is this also true for speech produced by people with aphasia? Our study shows that direct speech indeed contributes to perceived liveliness. However, no effect on comprehensibility is found.

Finally, we investigate whether direct and indirect speech constructions (e.g., John said that he had to leave) affect discourse comprehension differently in Dutch and English-speaking people with and without aphasia. This is indeed the case in Dutch: narratives containing direct speech are easier to comprehend than narratives with indirect speech for listeners with and without aphasia. However, in English this effect only exists for “healthy” listeners.