Which of the following is true according to recent research on human speech?

A) Humans do not show species-specific behavior relevant to speech.
B) Deaf children cannot benefit from language training after they are 4 years old.
C) There is a sensitive period for language acquisition in humans.
D) Overall, second-language learning is far more difficult for children than for adults.

Sensitive Period

A specific phase in an organism's development during which it is particularly receptive to certain environmental stimuli or experiences.

Speech

The verbal expression of thoughts, feelings, or information through the structured use of words, a fundamental aspect of human communication.

Language Acquisition

The process by which humans acquire the capacity to perceive, produce, and understand language, typically developing rapidly in the early years of life.