This project was formerly called ‘The influence of speech rate and voice quality on sentence comprehension’

Project members:

Birgitta Sahlén, Department of Logopedics, Phoniatrics & Audiology, Lund University
Marianne Gullberg, Humanities Laboratory, Lund University
Agneta Gulz, Cognitive Science, Lund University
Magnus Haake, Department of Design Sciences, Lund University
Kristina Hansson, Department of Logopedics, Phoniatrics & Audiology, Lund University
Viveka Lyberg-Åhlander, Department of Logopedics, Phoniatrics & Audiology, Lund University
Jonas Brännström, Department of Logopedics, Phoniatrics & Audiology, Lund University

The overall aim of the project is to study the influence of non-verbal factors as speech rate, voice quality and gesture on children’s language comprehension.  So far the influence of a speker’s speech rate (fast, normal and slow) and voice quality (typical and dysphonic) has been studied. Our aim is also to explore the role of working memory capacity and executive functioning for the processing of speech in different speech rate and voice quality conditions as well as environmental factors, like the sound environment.

So far, our results have showed that, for eight year olds with typical language development, a fast speech rate had a negative effect on the TROG 2 scores whereas the slow rate was more beneficial in general, although not in the most easy and most difficult tasks. For more difficult tasks the beneficial effect of slow speech was only pronounced for children with better scores on a working memory task. Our interpretation is that slow speech is particularly helpful when children are just about to grasp, but do not yet fully master a task. The results emphasise the necessity of careful considerations of the role dynamic aspects of the examiner’s speech might play in test administration and favour digitalised procedures in standardised language comprehension assessment.. This would ensure that voice quality, speech rate, gesturing, etc. are controlled for. Another advantage of a digitalised version lies in ensuring that it is always one and the same voice that occurs at different test occasions.

A study of the influence of a speaker’s voice quality on children’s language comprehension showed that children listening to a dysphonic voice achieved significantly lower scores for more difficult sentences (“the man but not the horse jumps”) and used more self-corrections on less difficult sentences (“the girl is sitting”), compared to children listening to a typical voice. Significant associations were found between the executive functioning test and the language comprehension test. This suggests that a dysphonic speaker’s voice may force the child to allocate capacity to the processing of the voice-signal at the expense of comprehension. This becomes particularly critical when the child is approaching her/his limits for mastering a comprehension task.

Our findings so far have direct implications for clinical and research settings where standardized language tests are used. Further, our results have implications for school settings. Our hypothesis is that a dysphonic teacher voice in combination with poor sound environment/room acoustics may increase the acoustic and cognitive challenge for children. We therefore continue this line of research in two ways. In an ongoing project we study how a speaker with typical vs dysphonic voice, speaking in different sound environments (background noise) influence children’s comprehension. Further, by developing a teacher avatar we will systematically vary the use of different non-verbal aspects of communication in order to find out the effect of gesture and voice in the ‘teacher’ on children’s comprehension.


Amnell, C., Sandberg, E. & Thulin, K. (2011). Talhastighetens betydelse för språkförståelsen. Magisterarbete i logopedi, Lunds universitet.

Anderberg, L., Johnell, A. & Lusena Halvardsson, E. (2012). Om sambandet mellan logopedens röstkvalitet, språkförståelse och kognitiv förmåga hos barnet. Magisterarbete i logopedi, Lunds universitet.

Haake, M., Hansson, K., Gulz, A., Schotz, S., & Sahlen, B. (2013). The slower the better? Does the speaker’s speech rate influence children’s performance on a language comprehension test? Int J Speech Lang Pathol. Early on line.

Lyberg-Ahlander, V. Haake, M., Brännstrom, J. Sahlén, B. (submitted) Does the speaker’s voice quality influence children’s performance on a language comprehension test? Submitted to the International Journal of Speech Language Pathology