The effects of direct and indirect speech on discourse comprehension in Dutch listeners with and without aphasia

Abstract

Background: Research on language comprehension in aphasia has primarily focused on comprehension of isolated words and sentences. Even though previous studies have provided insights into comprehension abilities of individuals with aphasia at the word and grammatical level, our understanding of the nature and extent of their language comprehension (dis)abilities is not yet complete. In contrast to the highly restricted semantic and syntactic interpretation of sentences, discourse comprehension requires additional pragmatic and non-linguistic skills.

Aims: The purpose of this study was to assess language comprehension in individuals with and without aphasia at the discourse level. In particular, it addressed the question of whether the use of direct speech, compared to indirect speech, affects comprehension of narrative discourse in Dutch aphasic and non-brain-damaged (NBD) listeners.

Methods & Procedures: The Direct Speech Comprehension (DISCO) test was developed to examine the effects of manipulating direct vs. indirect speech on discourse comprehension. Twenty-three individuals with aphasia and 20 NBD participants were presented with spoken narratives that contained either direct or indirect speech reports. The narratives were presented audio-visually on an iPad, and comprehension was assessed with yes/no questions.

Outcomes & Results: The performance of the participants with aphasia was significantly poorer than that of the NBD participants. Moreover, a main effect for condition type was found, indicating that narratives with direct speech reports were better understood than narratives with indirect speech reports by listeners with and without aphasia. There was no interaction between group and condition type indicating that this main effect held for both the aphasic and the NBD listeners. However, for the participants with aphasia, there was an interaction between condition and Token Test error score indicating that the positive effect of direct speech constructions diminishes for individuals with poorer comprehension.

Conclusions: Direct speech constructions facilitate language comprehension in listeners with and without aphasia. One explanation for this finding is the occurrence of additional “layers” of communication, such as intonation and facial expression, often accompanying direct speech constructions. An alternative account is the degree of grammatical complexity: In Dutch, the syntactic construction of indirect speech requires embedding, whereas in direct speech the introductory sentence and the quote are both main clauses. The finding that the beneficial effect of direct speech on language comprehension diminishes for individuals with severe aphasia may indicate that the DISCO is too difficult for them to reveal an effect of a subtle manipulation such as that of condition type.

Keywords:

• Aphasia
• Discourse comprehension
• Direct speech
• Indirect speech

This work is part of the research programme The Conversation Frame: Linguistic Forms and Communicative Functions in Discourse awarded to Dr. E. Pascual.

The research programme is financed by the Netherlands Organisation for Scientific Research (NWO). Lyndsey Nickels was funded by an Australian Research Council Future Fellowship.

Notes

¹ “a unit of language larger than the sentence” (Chafe, 1992, p. 35).

² The FRE test is designed to calculate comprehension difficulty, based on the number of words, sentences and syllables of a narrative, using the following formula: 206.835 – 1.015 × (total words/total sentences) – 84.6 × (total syllables/total words). Higher scores indicate material that is easier to read. Texts with scores between 60 and 69 are considered standard, those between 70 and 79 are considered fairly easy and those between 80 and 89 are considered easy (Flesch, 1948).

³ During this test, the participant receives instructions to perform tasks that increase in difficulty with a set of tokens differing in shape, colour or size, such as “show me the red square and the yellow circle”.

⁴ Further analyses show that the direct speech condition is easier than the indirect speech condition for participants with Token Test error scores up to 29 and that the effect disappears for participants with Token Test error scores above 30. However, this threshold should be interpreted with caution, as it is based on different sample sizes (n = 19 and n = 4, respectively).

⁵ Whilst it is clear that Example 3B has a changed word order (as compared to the reported word order, which is subject-verb-object (SVO)), it is not straightforward whether the SVO word order in Example 3A represents the base or the derived form. In Dutch, the position of the finite verb in main clauses differs from that in subordinate clauses. The unmarked order of main clauses is SVO, while subordinate clauses exhibit an SOV pattern. Therefore, which order is basic is a fundamental and highly debated problem in Dutch grammar. For many years, from the early 1970s, the general consensus was that Dutch (like German) is an SOV language (e.g., Bastiaanse, 2011; Bastiaanse, Hugen, Kos, & van Zonneveld, 2002; Bastiaanse & Zonneveld, 2006; Koster, 1975; Scaglione, 1981). However, new theories suggest that the SOV order is itself derived from a more basic SVO order (e.g., Den Dikken, 1996; Koster, 1994; Zwart, 1994, 1997). This linguistic debate regarding canonical word order in Dutch is beyond the scope of this article.