What enables native speakers to produce and understand sentences they have not heard nor used before?

• A. Language is arbitrary
• B. Language is creative
• C. Language is a system of systems
• D. Language is a means of communication

Answer: (B)

The main idea here is that language is creative and productive. Native speakers can produce and understand sentences they’ve never heard because they rely on a mental system of rules and representations that lets them combine words in novel ways. This rule-governed creativity—recursive, compositional structure—means a finite vocabulary and a finite set of grammar rules yield an infinite array of possible sentences. That’s why you can generate and interpret strings you’ve never encountered before, by applying those underlying rules. The other options point to important aspects of language, but they don’t explain the power to create and comprehend new sentences: language being arbitrary speaks to sign-meaning conventions, a system of systems describes how different subsystems fit together, and language as a means of communication addresses purpose rather than generation.