Interactions between youth with cognitive disabilities and unfamiliar adult partners were observed during a "standard partner" condition to discern the effects of the use of an augmentative and alternative communication system on communication patterns. Thirteen individuals who used the System for Augmenting Language (SAL) were compared to individuals who do not speak and who do not have SAL experience and individuals who speak. In general, the SAL users fell in the middle of the range, communicating better than the symbol-naive nonspeakers, yet not quite as well as the natural speakers with cognitive disabilities. These findings highlight the distinct contributions symbol experience makes to communication interactions with unfamiliar partners.