Smart speaker devices can improve speech intelligibility in adults with intellectual disability

Elizabeth Smith, Petroc Sumner, Craig Hedge, Georgina Powell

Research output: Contribution to journalArticlepeer-review


Background: Successful communication is vital to quality of life. One group commonly facing speech and communication difficulties is individuals with intellectual disability (ID). A novel route to encourage clear speech is offered by mainstream smart speakers (e.g., Amazon Alexa and Google Home). Smart speakers offer four factors important for learning: reward immediacy, spaced practice, autonomy/intrinsic motivation and reduced social barriers. Yet the potential of smart speakers to improve speech intelligibility has not been explored before. Aims: To determine whether providing individuals with intellectual disabilities with smart speaker devices improved ratings of speech intelligibility for (1) phrases related to device use and (2) unrelated words via a semi-randomized controlled trial. Methods & Procedures: In a semi-randomized controlled trial, an intervention group of adults with ID (N = 21) received smart speakers, while a control group (N = 22) did not. Before and after about 12 weeks, participants were recorded saying smart speaker-related phrases and unrelated words. Naïve participants then rated the intelligibility of the speech recordings. Outcomes & Results: The group that received smart speakers made significantly larger intelligibility gains than the control group. Although the effect size was modest, this difference was found for both smart speaker-related phrases and unrelated words. Conclusions & Implications: While the mechanism of action remains to be determined, the presence of smart speakers in the home had a demonstrable impact on ratings of speech intelligibility, and could provide cost-effective inclusive support for speech and communication improvement, improving the quality of life of vulnerable populations. What this paper adds What is already known on the subject Speech intelligibility is a key obstacle for social relationships and quality of life across several vulnerable populations (children with speech difficulties, older adults with dementia, individuals with ID). Anecdotal reports suggest mainstream smart speakers (e.g., Amazon Alexa, Google Home), could improve speech intelligibility. What this paper adds to existing knowledge We used a semi-randomized controlled trial to show that using a smart speaker for about 12 weeks could improve ratings of speech intelligibility in adults with ID for both smart speaker-related phrases and unrelated words. What are the potential or actual clinical implications of this work? These initial findings suggest that smart speaker technology could be a novel, and inclusive, route to improving speech intelligibility in vulnerable populations.

Original languageEnglish
Pages (from-to)583-593
Number of pages11
JournalInternational journal of language & communication disorders
Issue number3
Early online date27 Mar 2021
Publication statusPublished - 24 May 2021

Bibliographical note

© 2021 The Authors. International Journal of Language & Communication Disorders published by John Wiley & Sons Ltd on behalf of Royal College of Speech and Language Therapists. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Funding: This research was funded by a Health and Care Research Wales Fellowship (grant number SCF-18-1504). The authors thank Innovate Trust, Cardiff, UK, and all participants for supporting this research.


  • communication
  • intellectual disability
  • intelligent personal assistants
  • smart speakers
  • speech intelligibility


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