Background sounds at home-namely those from television, communication devices, music, appliances, transportation, and construction-can support or impede infant language interactions and learning. Yet real-time connections at home between background sound and infant-caregiver language interactions remain unexamined. We quantified background sounds in the home environment, from 1- to 2-hr video recordings of infant-mother everyday activities (infants aged 8-26 months, 36 female) in two samples: European-American, English-speaking, middle-socioeconomic status (SES) families (N = 36) and Latine, Spanish-speaking, low-SES families (N = 40). From videos, we identified and coded five types of background sound: television/screens, communication devices, music, appliances, and transportation/construction. Exposure to background sounds varied enormously among homes and was stable across a week, with television/screens and music being the most dominant type of background sounds. Infants' vocalizations and mothers' speech to infants were reduced in the presence of background sound (although effect sizes were small), highlighting real-time processes that affect everyday language exchanges. Over the course of a day, infants in homes with high amounts of background sounds may hear and produce less language than infants in homes with less background sounds, highlighting potential cascading influences from environmental features to everyday interactions to language learning. (PsycInfo Database Record (c) 2024 APA, all rights reserved).