On Umbrellas and Omnibuses: A Response to Open Peer Commentaries

Abstract This response to the commentaries on our conceptual review article on structural complexity and learning difficulty in second language acquisition (SLA) clarifies the scope and objectives of our framework, the challenges of defining and measuring complexity and difficulty, and the broader relevance of our proposal for both empirical research and theory building in SLA, including its relationships to frameworks such as complexity–accuracy–fluency (CAF).