Music in first language acquisition

In the current chapter, we address infants’ language-acquisition challenges in extracting regularities (such as phonemes, words and phrases) from the variable acoustic input of the continuous signal of both speech and song. We review the (musical) characteristics of infant-directed speech and song, including pitch characteristics, speech rate, boundary marking, rhythm and repetition, and the evidence for potential benefits of these characteristics for language development. Compared to adult-directed speech, infant-directed speech is generally slower and higher pitched, contains many repetitions and shows stronger rhythmic regularity, combined with higher pitch variability and enhanced boundary marking. Songs are highly captivating for infants, and song exposure is positively associated with infants’ language development. Infant-directed song is inherently rhythmical, with pitch being bound to the melody, resulting in a predictable temporal and melodic structure. Benefits for language acquisition might arise because musical characteristics in infant-directed communication help the infant to learn where, how, and when to focus their attention. This is essential for identifying and memorizing linguistic units and structure at different timescales. While rhythmic regularity and repetition increase predictability and might set up a scaffold facilitating (neural) processing, variability in both tempo and pitch could draw attention to specific parts within this scaffold. This way, musical characteristics in infant-directed speech and song might help infants to discover meaningful units and structure in the input, facilitating further language learning.