Final answer:
Developmental variation is seen in temperament, academic skills, and motor development as children grow, but not in the sequence of language acquisition. While individual timing of language milestones may differ, the order in which language skills develop is consistent worldwide.
Step-by-step explanation:
The areas in which rates of development can vary as children and adolescents mature into adults are temperament, academic skills, and motor development. However, language development is not an aspect where variation is expected in sequence; while the timing may differ, the sequence in which language skills are acquired is consistent across cultures and children.
Developmental psychologists identify three domains of human development, but temperament is not one of them. Though temperament, defined as inborn personality differences, plays a crucial role in how children express their personalities as influenced by their environment and maturation. On the other hand, academic skills, like reading and writing, can widely vary among individuals based on educational opportunities and other factors. Motor development, while generally following a certain sequence, can be influenced by cultural practices, thus showing variation in the rate of achieving developmental milestones. Language, however, is acquired in a similar sequence worldwide, despite differences in the age at which specific milestones are reached.
Focusing on the sequence of development, research shows that certain cognitive abilities develop through to the early 20s, with adolescents demonstrating adult-like levels of cognition by the age of 15 or so. Aspects of cognitive and motor skills progress through stages with adolescence being a time of rapid development both physically and mentally.