biostudies-literatureHilton CBMPIEANSERCSSHRCIAST ANRRoyal Society of New ZealandFIC NIH HHSNIAID NIH HHSU.S. Department of Health & Human Services | NIH | NIH Office of the DirectorHarvard Data Science InitiativeHarvard University Department of PsychologyAcademy of FinlandBritish AcademyFondation Pierre MercierFogarty International CenterFogarty International CenterNHLBININDSNIAIDHarvard College Research ProgramPolish Ministry of Science and Higher EducationFogarty International CenterNINDSNHLBIHarvard University Department of PsychologyU.S. Department of Health & Human Services | NIH | NIH Office of the Director (OD)NIH HHS1545-1556https://www.ebi.ac.uk/biostudies/studies/S-EPMC10101735biostudies-literatureUnknown6(11)When interacting with infants, humans often alter their speech and song in ways thought to support communication. Theories of human child-rearing, informed by data on vocal signalling across species, predict that such alterations should appear globally. Here, we show acoustic differences between infant-directed and adult-directed vocalizations across cultures. We collected 1,615 recordings of infant- and adult-directed speech and song produced by 410 people in 21 urban, rural and small-scale societies. Infant-directedness was reliably classified from acoustic features only, with acoustic profiles of infant-directedness differing across language and music but in consistent fashions. We then studied listener sensitivity to these acoustic features. We played the recordings to 51,065 people frNature human behaviourAcoustic regularities in infant-directed speech and song across cultures.PMC10101735D43 TW010540DP5OD024566298513R15 AI128714DP5 OD024566Trehub SEAnyawire MJasienska GSchachner AAmir DBainbridge CMAlemu ERoss CTGlowacki LHilton CBWood BMKim MMabulla AScaff CCutipa SCVardy TAPlacek CDMoya CSalali GDSingh MStieglitz JBertolo MGalbarczyk ACirelli LKSimson JAndelin JKeestra SLee-Rubin HSalenius AMoser CJSiddaiah AKrasnow MMAntfolk JMehr SAKnox DSong JMartin ANeff MBCollins SAAtkinson QDSagar RRMadhivanan PPatton JQfalseAcoustic regularities in infant-directed speech and song across cultures.When interacting with infants, humans often alter their speech and song in ways thought to support communication. Theories of human child-rearing, informed by data on vocal signalling across species, predict that such alterations should appear globally. Here, we show acoustic differences between infant-directed and adult-directed vocalizations across cultures. We collected 1,615 recordings of infant- and adult-directed speech and song produced by 410 people in 21 urban, rural and small-scale societies. Infant-directedness was reliably classified from acoustic features only, with acoustic profiles of infant-directedness differing across language and music but in consistent fashions. We then studied listener sensitivity to these acoustic features. We played the recordings to 51,065 people fr2022-01-01T00:00:00Z2022 Nov2025-07-10T03:08:13.487Z2025-04-19T23:47:08.977ZS-EPMC101017353585184310.1038/s41562-022-01410-x