Purpose: The aims of this article are twofold: (a) to offer a set of recommended measures that can be used for evaluating the efficacy of interventions that target spoken language acquisition as part of treatment research studies or for use in applied settings and (b) to propose and define a common terminology for describing levels of spoken…

Children with Down syndrome often display speech-comprehensibility and grammatical deficits beyond what would be predicted based upon general mental age. Historically, speech-comprehensibility has often been treated using traditional articulation therapy and oral-motor training so there may be little or no coordination of grammatical and…