“…Development of presymbolic communication has been described for individuals with different types of disabilities and disorders including hearing impairment (Zaidman-Zait & Dromi, 2007), brain lesions (Bates, Vicari, & Trauner, 1999), autism (Luyster, Qiu, Lopez, & Lord, 2007; Chian, Soong, Lin, & Rogers, 2008; Wetherby, et al, 2004), Down syndrome (Abbeduto, Warren, & Conners, 2007; Fidler, Philofsky, Hepburn, & Rogers, 2005), Williams syndrome (Singer-Harris, Bellugi, Bates, Jones, & Riossen, 1997), Angelman syndrome (Didden et al, 2009) and fragile X syndrome (Flenthrope & Brady, 2010). For example, children with Down syndrome typically have a profile of relative strength in gesture use across communicative functions (Abbeduto et al, 2007; Brady et al, 2008) whereas children with autism frequently have an uneven profile characterized by infrequent commenting gestures (Anderson et al, 2007; Kasari, Freeman, & Paparella, 2006)…”