How bilingualism alters non-tone-learning infants' tone perception in the first year of life

Infants’ perceptual sensitivity changes during the second half of the first year of life from distinguishing virtually all speech contrasts to tuning in to the native phonemic inventory, a process known as perceptual reorganization (PR). During this process, infants maintain and improve their ability to perceive the relevant contrasts for the native language and more importantly, their sensitivity to most non-native contrasts deteriorates