Final answer:
Universal Phoneme Sensitivity allows infants to discern phonemes from all languages but starts to wane by the age of 1 year, with children losing sensitivity to phonemes not used in their environment.
Step-by-step explanation:
Universal Phoneme Sensitivity is a phenomenon observed in infants, where they have the ability to discriminate among the sounds that make up all human languages. This remarkable ability allows them to perceive differences between phonemes across different languages, even those that are not present in their immediate linguistic environment. However, as babies grow, they begin to specialize in the phonemes that are relevant to the languages they hear around them.
Research indicates that Universal Phoneme Sensitivity begins to diminish around the age of 1 year. By this time, infants start to lose their sensitivity to phonemes that are not part of the language or languages they are exposed to daily. As a result, their perceptual abilities begin to reflect the phonemic structure of the languages that are spoken in their environment, showing a specialization that aids in language acquisition.