Adults with developmental disabilities and educational researchers have identified many holes in the practices currently used to educate non-speaking youth with developmental disabilities, especially those with extensive support needs (Kapp, 2020; Taub, et al., 2017). While technology cannot provide a magical, sweeping fix to barriers to inclusion, the increasing availability of educational and consumer technologies does open new, understudied possibilities for how students with developmental disabilities, especially non-speaking students who utilize these tools as speech prostheses, can engage in schoolwork and beyond (Alper, 2017; Krishnan, 2021; Skouge, 2014). In order to better understand how they learn, it is imperative that we understand how they make sense of the world: their epistemic practices. Very little is known about the epistemic practices that non-speaking students with developmental disabilities engage in when learning, especially with respect to their embodied cognition and use of new media. New media must therefore be included in the study of non-speaking people with developmental disabilities' epistemic practices. A better understanding of how these learners learn is necessary to conduct design research and implement improved educational opportunities. In order to fill this gap in the research, this study asked what epistemic practices non-speaking people with developmental disabilities and extensive support needs developed in their learning environment. First, I learned from members of this community who engaged in a nature walk curriculum at a Non-Public school. Then, I used my completed data analyses to develop a series of design principles and an initial theory about what epistemic practices are cripistemologically valid for nonspeaking people with developmental disabilities and extensive support needs, and how researchers and practitioners might use these principles for future work. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]