Johnson, E. K., Westrek, E., Nazzi, T., & Cutler, A. (2011). Infant ability to tell voices apart rests on language experience. Developmental Science,14(5), 1002-1011. doi:10.1111/j.1467-7687.2011.01052.x.
A visual fixation study tested whether seven-month-olds can discriminate between different talkers. The infants were first habituated to talkers producing sentences in either a familiar or unfamiliar language, then heard test sentences from previously unheard speakers, either in the language used for habituation, or in another language. When the
language at test mismatched that in habituation, infants always noticed the change. When language remained constant and only talker altered, however, infants detected the change
only if the language was the native tongue. Adult listeners with a different native tongue than the infants did not reproduce the discriminability patterns shown by the infants, and infants detected neither voice nor language changes in reversed speech; both these results argue against explanation of the native-language voice discrimination in terms of acoustic
properties of the stimuli. The ability to identify talkers is, like many other perceptual
abilities, strongly influenced by early life experience.