Final answer:
Young infants show the ability to hear the difference between speech sounds. At birth, they can recognize their mother's voice and distinguish it from others. However, as they grow older, their ability to discriminate among all human phonemes diminishes.
Step-by-step explanation:
Young infants show the ability to hear the difference between speech sounds. At birth, babies can recognize their mother's voice and distinguish it from other voices.
They also have a preference for human voices and show a greater attention to speech sounds compared to other sounds. However, as they grow older, their ability to discriminate among all human phonemes diminishes, and they can only differentiate between the sounds used in the languages spoken in their environment.