Final answer:
Both noisy and silent environments can be inappropriate for infant language development. Noisy environments may startle and scare infants, while silent environments fail to provide necessary auditory stimulation.
Step-by-step explanation:
Concerning the language environment for infants, inappropriate settings can hinder their development. When assessing such environments, both extremes of noise levels can be inappropriate. Noisy environments are known to startle and scare newborns. They can lead to increased attention to potential danger signals such as angry voices, thunder, or other infants' cries. Conversely, silent environments provide none of the stimulation required for healthy auditory and speech development.
Therefore, the answer to the question “Which of the following is part of an inappropriate language environment for infants?” is d. both noisy and silent environments. A balance between quiet and sound is essential for proper language and auditory development in infants, avoiding the extremes of overstimulation or complete silence.