In the context of the one-word stage, underextension means the word is too narrow and overextension means it is too broad. Which choice best describes this concept?

• A. Semantic misapplication of word meanings
• B. Phonological development
• C. Syntactic rules
• D. Pragmatic development

Answer: (A)

In the one-word stage, children are figuring out what words mean and how broadly to apply them. Underextension happens when a child uses a word to refer to only a small, specific set of things—too narrowly. For example, calling only their own ball “ball” but not other balls, or using “dog” only for their family pet. Overextension is the opposite: a child uses one word for many different things, too broadly—like calling all four-legged animals “dog” or all vehicles “car.” These patterns show how meaning of words is still developing and being mapped to experiences.

The best description here is semantic misapplication of word meanings, because it targets how children attach meanings to words and how those meanings can be either too restricted or too broad. The other options point to different areas: phonological development deals with sounds; syntactic rules with grammar and sentence structure; pragmatic development with social use and context of language.