Cochlear implant-related speech processing may diminish the advantage of exposure to infant-directed speech

ABSTRACT Caregivers modify their speech when talking to infants, a specific type of speech known as infant-directed speech (IDS). This speaking style facilitates language learning compared to adult-directed speech (ADS) in infants with normal hearing (NH). While infants with NH and those with cochlear implants (CIs) prefer listening to IDS over ADS, it is yet unknown how CI speech processing may affect the acoustic distinctiveness between ADS and IDS, as well as the degree of intelligibility of these. This study analyzed speech of seven female adult talkers to investigate the effects of simulated CI speech processing on (1) acoustic distinctiveness between ADS and IDS, (2) estimates of intelligibility of caregivers’ speech in ADS and IDS, and (3) individual differences in caregivers’ ADS-to-IDS modification and speech intelligibility. Results suggest that CI speech processing is substantially detrimental to the acoustic distinctiveness between ADS and IDS, as well as to the intelligibility benefit derived from ADS-to-IDS modifications. Moreover, the observed considerable variability across individual talkers in acoustic implementation of ADS-to-IDS modification and speech intelligibility was significantly reduced due to CI speech processing. The findings are discussed in the context of the link between IDS and language learning in infants with CIs.