Infant-directed speech becomes less redundant as infants grow: Implications for language learning

Research output: Contribution to journalArticlepeer-review


Do speakers use less redundant language with more proficient interlocutors? Both the communicative efficiency framework and the language development literature predict that speech directed to younger infants should be more redundant than speech directed to older infants. Here, we test this by quantifying redundancy in infant-directed speech using entropy rate – an information-theoretic measure reflecting average degree of repetitiveness. While IDS is often described as repetitive, entropy rate provides a novel holistic measure of redundancy in this speech genre. Using two developmental corpora, we compare entropy rates of samples taken from different ages. We find that parents use less redundant speech when talking to older children, illustrating an effect of perceived interlocutor proficiency on redundancy. The developmental decrease in redundancy reflects a decrease in lexical repetition, but also a decrease in repetitions of multi-word sequences, highlighting the importance of larger sequences in early language learning.

Original languageAmerican English
Article number105817
StatePublished - Aug 2024


  • Efficient communication
  • Entropy rate
  • Infant-directed speech
  • Multi-word sequences
  • Redundancy

All Science Journal Classification (ASJC) codes

  • Experimental and Cognitive Psychology
  • Developmental and Educational Psychology
  • Cognitive Neuroscience
  • Language and Linguistics
  • Linguistics and Language


Dive into the research topics of 'Infant-directed speech becomes less redundant as infants grow: Implications for language learning'. Together they form a unique fingerprint.

Cite this