Children with Down syndrome (DS) face life-long struggles with verbal communication. Babble and speech sound development is delayed, and speech can be difficult to understand. Words emerge late, at 21 months on average, compared to 12 months for typical peers, and vocabulary and grammar can remain limited throughout adulthood. Because DS is diagnosed at or even before birth, these difficulties are predictable; yet despite this prognostic knowledge, systematic and sustained proactive interventions have not yet been developed: Most children with DS are not assessed and treated for speech and language delays until age 2 to 4 years. This presents an untapped opportunity space to conduct a clinical trial of a proactive intervention in earliest infancy with the goal of building resilience against the anticipated difficulties. The intervention trialed here is a modified version of Babble Boot Camp (BBC), a proactive speech and language intervention originally developed for young infants with classic galactosemia (CG) (NIH 5R01HD098253). CG is a metabolic disease that, similar to DS, is diagnosed at birth and poses risks for severe speech and language delays. BBC is implemented by a speech-language pathologist who, via telehealth, trains parents to incorporate skill-building activities and routines into their daily lives at home. For the present study, 20 children with DS age birth to 12 months will be recruited and randomized into two treatment arms. One group will receive weekly individualized parent sessions and close monitoring of the child's progress. The second group will receive the same content but at a lower intensity and dosage, via monthly parent group meetings. Both groups will receive their intervention for 10 months. Specific aims are to quantify benefits for babble, speech production, and receptive and expressive language and to investigate associations between conversational dynamics in child-adult interactions and the children's speech and language. Outcomes in speech and language skills will show relative feasibility and benefits for each of these treatment modalities and motivate a larger clinical trial, with the ultimate goal of changing the way infants with DS receive support in their speech and language development, from a deficit-based, remedial model to a proactive one.