1. Department of Communication Sciences and Disorders, Idaho State University Health Sciences Centre, Meridian, ID, USA
2. Department of Communication Sciences and Disorders, University of Texas, Austin, TX, USA
3. Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Centre, Lubbock, TX, USA
4. Department of Communication Sciences and Disorders, Northeastern University, Boston, MA, USA
5. Boston Children’s Hospital, Waltham, MA, USA
6. Centre for Augmentative and Alternative Communication/Pretoria, University of Pretoria, South Africa