Phonetic categorisation and cue weighting in adolescents with Specific Language Impairment (SLI)

Abstract

This study investigates phonetic categorisation and cue weighting in adolescents and young adults with Specific Language Impairment (SLI). We manipulated two acoustic cues, vowel duration and F1 offset frequency, that signal word-final stop consonant voicing ([t] and [d]) in English. Ten individuals with SLI (14.0–21.4 years), 10 age-matched controls (CA; 14.6–21.9 years) and 10 non-matched adult controls (23.3–36.0 years) labelled synthetic CVC non-words in an identification task. The results showed that the adolescents and young adults with SLI were less consistent than controls in the identification of the good category representatives. The group with SLI also assigned less weight to vowel duration than the adult controls. However, no direct relationship between phonetic categorisation, cue weighting and language skills was found. These findings indicate that some individuals with SLI have speech perception deficits but they are not necessarily associated with oral language skills.

• Adolescents
• cue weighting
• Specific Language Impairment (SLI)
• speech perception

Acknowledgements

The authors would like to thank the children and adults who took part in the study and members of the Centre for Developmental Language Disorders and Cognitive Neuroscience. We would also like to thank the two anonymous reviewers for their suggestions and comments.

Heather van der Lely died of cancer in February 2014, before this paper had been finalised for submission for publication. Heather van der Lely had a personal interest in the VATT and TAPS tests.

Funding

This research was supported by Wellcome Trust Grant (063713) awarded to Heather van der Lely and was carried out at the Centre for Developmental Language Disorders and Cognitive Neuroscience at UCL.

Declaration of interest

The authors report no conflicts of interest. The authors are responsible for the content and writing of the paper.

Notes

¹BPVS-II is standardised on children up to the age of 15.8; TWF-2 up to 12.11; TROG-2 up to 16.0 CELF-3 up to 21.0 years. Where individuals were older than these cut-off ages, their raw scores on the tests were converted to standard scores at the ceiling level for the individual test.

²Ramus et al. (2013) tested 65 TD children aged between 5 and 12 years and reported mean z-scores of 0.06 (SD = 0.87) and 0.01 (SD  =  0.77) for TAPS and VATT, respectively.