Open Access. The accepted version of this article has been reproduced here according to the publisher's policies.
This is an Accepted Manuscript of an article published by Taylor and Francis in International Journal of Speech-Language Pathology on 07 March 2017, available online: https://www.tandfonline.com/10.1080/17549507.2017.1290137 (Please note: access via this link may only be available with a subscription).
Copyright (2017) Taylor and Francis
International Journal of Speech-Language Pathology, 19(3): 277-286