Depending on the severity of their disabilities, children with Down syndrome (DS) and with cerebral palsy (CP) may remain pre-symbolic for prolonged periods of time. When interacting with pre-symbolic children, communication partners have a role in identifying which of their behaviours are communicative, to be able to respond to those behaviours and maintain reciprocal interaction. To date, most research on these children's communication development has been conducted within the context of mother-child interaction. Seldom have they been observed interacting with other family members, and in interactions other than dyadic, despite these interactions also occurring daily.