Engagement in music and singing may be a valuable tool to support or develop speech skills in people with DS, as it is for TD populations. However, to the author's knowledge, no study has yet examined in detail the musical abilities of people with DS, or whether the conditions that support the transfer of learning from the musical domain to the speech domain (Patel, 2011; 2014) may be met. This study explores the potential value of musical learning to support speech perception and production in the population. A set of case studies with multiple measures were used to assess the cognitive, speech, vocal and musical abilities of four young adults with DS and SLD, who participated in four sessions of a sixweek programme of song-based musical activities. Their progress in learning new songs was tracked during this time. Participants had physiological, cognitive and perceptual difficulties that were common to speech and musical domains. These included a low digit span and attentional difficulties, dysfluency, and evidence of dysphonia and diplophonia in speech and song. However, their voice quality, in particular, varied according to task demands. Individuals made progress in mastering new songs and in imitating pitch and interval-matching tasks. They were able to transfer learning from songs to the spoken domain. Differences in the performance of individuals in both domains could be primarily attributed to previous learning, hearing status, and to task effects. Aspects of music-based learning appeared to support the perception and production of speech in the four participants. The study concluded that music activities might be an appropriate means of supporting aspects of speech development in people with DS. A programme of musical activities is recommended that could support the perceptual and productive speech difficulties that are common to the wider DS population.