The needs of the severely disabled, especially in communities where there is a paucity of professional manpower inspired this research aiming at the refinement and validation of a play package consisting of a daily multiple measurement instrument and a package of play activities for the facilitation of communication-related behaviours. This intervention programme is based on theoretical underpinnings derived from various scientific disciplines' explanations of sensorimotor, cognitive, communication and social-emotional development, as well as the role of play as a facilitator of childhood development. Within this theoretical context a model for the development of communication-related behaviours as adaptive responses is put forward. Through a process of operationalisation of the relevant constructs, observable behavioural indicators are identified and applied to the developmental needs of the intellectually impaired. Play is described as a tool for the facilitation and measurement of communication-related behaviours and within this framework an authentic daily multiple measurement instrument (DMMI) was developed and a package of play activities (previously developed) refined for validation through experimentation. The main aim of the empirical research was to validate the play package for the facilitation of communication-related skills by the refinement of the play package consisting of specifically selected activities and presentation methods during a pre-experimental phase, as well as experimentation to establish a cause-effect relationship between the activities and changes in single, gradually acquired behaviours of children with intellectual impairments. In the pre-experimental phase face and content validity were investigated by a group of experts who evaluated the daily multiple measurement instrument and the package of play activities, as well as the audio-visual recordings of the measurement and treatment of intellectually impaired children in two pilot studies. During the experimental phase construct and convergent validity were investigated. Data were collected from five intellectually impaired participants over an eight week period in which week 1 was used for pre-intervention measurements, weeks 2, 3 and 4 for intervention, week 5 for post-intervention measurements, weeks 6 and 7 for a period of withdrawal and week 8 for post-withdrawal measurements. External raters were involved to assure reliability and three additional authentic measurement instruments were included for the establishment of convergent validity. Based on the findings of the research face, content, construct and convergent validity of the play package was established, thus proving that the daily multiple measurement instrument measures the behaviour that it claims to measure and the package of play activities facilitates the development of communication-related behaviours that it claims to facilitate. A valid and reliable play package, catering for the individual needs of the heterogeneous population of disabled children, was thus established. The play package is structured in such a way that it can be applied by any member of a transdisciplinary team, and even (with some prior training) by non-professional caregivers and parents, thus alleviating the burden on a handful of professional therapists who cannot cope with the needs of the large population of severely disabled children. / Dissertation (PhD (Augmentative and Alternative Communication)--University of Pretoria, 2004. / Centre for Augmentative and Alternative Communication (CAAC) / unrestricted