Enhancing communication performance skills may help children with Down Syndrome (DS) to expand their opportunities for participation in daily life. It is a clinical challenge for speech-language pathologists (SLP) to disentangle various mechanisms that contribute to the language and communication problems that children with DS encounter. Without clarity of different levels of functioning, appropriate interventions may be poorly conceived or improperly implemented. In the present study, the International Classification of Functioning, Disability and Health-Children and Youth Version (ICF-CY) framework was used to classify contributing factors to communication performance in a multiple case study of six young children with DS. Within a comprehensive assessment, we identified individual and environmental facilitators and barriers, leading to an integrative profile of communication performance (IPCP) for each child. Whereas these six children shared a developmental, and/or expressive vocabulary age and/or level of communicative intent, the children faced similar but also unique personal and environmental factors that play an important role in their communication performance. Our data reveal that a combination of different factors may lead to the same language outcomes and vice versa, based on a unique pattern of interdependency of ICF-CY domains. Planning SLP interventions for enhancing communication performance in children with DS should therefore be based on a comprehensive view on the competences and limitations of every individual child and its significant communication partners. This evaluation should address facilitators and barriers in body functions, structures, activities, participation and environment, with a specific focus on individual strengths. The ICF-CY provides a useful framework for constructing an IPCP that serves this purpose.