The current phenomenological case study, based in part on Vygotsky's sociocultural theory, set out to examine the lived experiences of individuals sharing and mediating meaningful communication with individuals who have Down syndrome. To accomplish this, the researcher interviewed several categories of caregivers who regularly interact with children diagnosed with Down syndrome: parents, teachers, and childcare providers. In addition, two adults diagnosed with Down syndrome were interviewed. The data was analyzed using horizontalization and constant comparative method of analysis. Within-case and cross-case analysis was performed to compare the categories of participants. The results from the qualitative analysis revealed a number of overall themes. First, the findings suggest that no clear, consistent, long-term mediating tool use was evident across settings, including sign language. Second, the current study raises the question of a possible relationship between early sign language use and later deficits in specific parts of speech. Further research is needed to examine if this relationship is found in a larger population of adults with Down syndrome whose parents used sign language in infancy and early childhood. Third, findings in the current study refer universally to frustration experienced by the child or adult with Down syndrome, which can result in cessation of all communication, stubborn refusal to cooperate, or unwillingness to engage in the process of education. Fourth, all participants consistently agreed upon the social nature of children and adults with Down syndrome, particularly with other special needs students, which suggests an avenue of mediation worthy of further investigation. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]