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 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 caregivers 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 one of two treatment arms. One group will receive weekly individualized caregiver 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 caregiver group meetings. Both groups will receive their intervention for 10 months. At the beginning and end of the intervention, a set of data will be collected: At the beginning of the interventions, caregivers will be asked to complete an intake questionnaire with demographic information and information about the child's birth history, health history, and any services currently accessed. At the end of the intervention, caregivers will provide updates to this questionnaire and also a satisfaction survey. At pre and post, caregivers will provide three daylong audio recordings that will be analyzed for child utterance rates and conversational turns. For children age 6 months and up. these recordings will also be queried for segments with greatest numbers of child utterances, and these will be transcribed into International Phonetic Alphabet to obtain an objective measure of babble complexity, using the Mean Babbling Level, and, if sufficient numbers of meaningful utterances are found, an objective measure of word complexity using the Syllable Structure Level. At pre and post, questionnaires will be collected to appraise the children's general development and communication competence, using the Vineland Adaptive Behavior Scales 3. More detailed measures of early language skills, such as receptive and expressive vocabulary, will be obtained with the MacArthur-Bates Communicative Development Inventories -3. Age at emergence of first words will be recorded as a personal milestone for each child. Regarding parental well-being, the Parenting Stress Index 4 Short Form will be collected to obtain measures of stress originating in the parents themselves, in parent-child interactions, and in difficult child behaviors. This questionnaire also contains an estimate of whether or not parents are under-reporting their own personal stress. Specific aims are to quantify 1) benefits of each of the two interventions for babble and early speech sound production, 2) benefits of each of the two interventions for receptive and expressive language skills, and 3) associations between caregiver-child conversational dynamics during the intervention and child speech and language skill after the intervention. Outcomes in speech and language skills will show relative feasibility and benefits for each of these treatment modalities on children's speech and language development as well as parental well-being, and they will 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.