This document discusses comparing and contrasting first and second language acquisition. It begins by outlining types of comparisons that can be made, including comparing first and second language acquisition in children, second language acquisition in children and adults, and first language acquisition in children and second language acquisition in adults. The document then discusses considerations for these comparisons, including the critical period hypothesis, neurological considerations, psychomotor considerations, cognitive considerations, and affective considerations. It aims to analyze differences and draw insights from systematic study of first language learning to help understand challenges with second language learning.