The role of rhythm in the development of speech perception and production

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Unlike any other species, humans are rhythmic beings. The sounds of language and music, our two uniquely human communication systems, are rhythmically organized. They both display recurrent patterns of sound, such as syllables, notes and phrases that are predictable in time. In speech, mastering rhythm and timing is a crucial skill to interact and to keep in time together during conversation. Despite significant progress in rhythm research in the last decade, the underlying cognitive and motor mechanisms of how rhythm shapes speech perception and production are still poorly understood, especially in developmental populations. It is unclear, whether, during development, speech is produced and perceived using speech-specific or / and domain-general rhythmic mechanisms. To answer this question has important consequences for our understanding of how rhythmic capacities of different communication skills (music, speech) intertwine and may benefit speech development at different stages of development. To shed new light on these issues, the present research program will provide new insights into the role of rhythm (in particular, predictive timing) for the acquisition of critical speech capacities in infants and children/adolescents (i.e., speech sound perception, fluent speech production). The aim of a first series of experiments is to determine whether rhythmic predictions in speech and song help infants in their first year of life to process native and non-native speech in sung and spoken stimuli. Here, oscillatory dynamics will be measured (using EEG) to examine how infants neurally encode speech sounds when presented in more or less predictable rhythms of music and language. The second series of experiments tests the hypothesis that the development of fluent speech production in late childhood / adolescence is conditioned by precise, domain-general predictive timing skills. Participants will include children and adolescents (9-17 years) with and without a developmental speech fluency disorder (stuttering). The capacity to precisely predict and time a motor response to an auditory target will be compared in both groups using musical and speech synchronization tasks (such as finger tapping or speaking with a metronome). Moreover, it will be examined if improving skills in non-verbal synchronization also affects speech fluency skills. Indices of timing ability to music and speech will be used to determine whether domain-general timing processes drive the (faulty) development of speech fluency. The expected findings will provide new insights into the role of timing mechanisms in infants' and adolescents' speech acquisition. Overall, the findings will advance our knowledge on the (neuro)cognitive links underlying rhythmic processing in speech and music and provide opportunities to develop novel applications to foster speech development in children with delays or speech disorders.