Vocabulary: How not What

I found myself in conversation with another commuter on public transport today. They mentioned not completing high school in regards to their education, and the conversation drifted toward my interest in language and communication. I explained that vocabulary is never a reliable proxy for intelligence. A small vocabulary used precisely often reveals more intellect than an expansive one deployed reflexively. It is not what one possesses, but how it is used. A wide linguistic or conceptual range can indicate high intelligence, but it is neither required nor decisive.