This paper offers a comparative analysis of first–language acquisition and second–language acquisition, focusing on their distinct processes, challenges, and influencing factors. Grounded in the works of Piaget, Chomsky, and Vygotsky, this study examines the cognitive and social dimensions of language learning. First–language acquisition, as highlighted by Chomsky’s theory of a universal grammar, is an innate and subconscious process occurring during early childhood within the critical period. Piaget and Vygotsky emphasize the role of cognitive development and social interaction in shaping language acquisition, both of which are foundational to understanding second–language acquisition. In second–language acquisition, factors such as age, motivation, and prior linguistic knowledge play significant roles, alongside challenges such as transfer effects and fossilization. Drawing on interdisciplinary research in linguistics, psychology, and philosophy, this paper identifies parallels and divergences between first–language acquisition and second–language acquisition. It further explores the implications of these insights for educational strategies, based on data taken from Chomsky’s generative grammar framework and Vygotsky’s social constructivist perspective. By bridging philosophical theories and empirical findings, this study contributes to a deeper understanding of language acquisition and informs of methods for optimizing language learning across different age groups and contexts.