Which of the following linguistic skills typically develops last in human development?

The correct answer highlights that turning and looking in the direction of sounds is a skill that typically develops later in human linguistic development compared to the other skills listed. This skill involves not only the ability to hear sounds but also the capacity for spatial awareness and visual tracking, which are more complex cognitive functions.

In early stages of development, infants focus more on immediate sensory experiences and emotional expressions, such as crying for needs or vocalizing excitement or displeasure. These foundational vocalization and response skills develop earlier as they are closely linked to basic communication and emotional expression.

The ability to respond to changes in the tone of a speaker’s voice, while complex, typically develops around the same time as other early communicative responses due to the infant's growing understanding of emotional cues and the necessity of social interaction. In contrast, the more advanced skill of turning and looking toward sounds involves an integrated response that reflects both auditory and visual processing abilities, which take more time to fully develop in children.