The role of auditory-motor speech processing and higher cognitive abilities in language acquisition

Children appear to be better language learners than adults. The precise reason why remains unclear. Language learning is complex and involves unconsciously picking up statistical regularities from continuous streams of speech sounds, such as word boundaries or rules on word order. Our previous work shows that higher cognitive abilities interfere with statistical learning processes in adults. This provides a plausible first explanation for why adults do not learn language as effortlessly as children do. New evidence also suggests that the ability to synchronize speech movements with auditory rhythms is associated with the ability to learn language. It is well-known that the motor mechanisms that control speech movements are crucially involved in understanding speech, but the exact role that they play in language learning remains unknown. In the present proposal, we aim to test the hypothesis that auditory-motor speech processes contribute to implicit language learning, but interfere with higher cognitive abilities as a function of age. This will be investigated by using noninvasive brain stimulation and a cross-sectional design in which different age groups are compared on speech synchronization abilities, cognitive functions and language learning. The findings will advance our theoretical understanding of why children are better language learners than adults, and bring new insights in how cognitive development affects (a)typical language learning across the human life span.