This paper examines the distinct processes through which children and adults acquire English as a second or foreign language. Drawing on the Critical Period Hypothesis, it highlights children’s heightened neuroplasticity and their propensity to absorb phonological and grammatical structures intuitively. In contrast, adults often rely on metalinguistic analysis and explicit instruction, leveraging life experience to accelerate reading and writing skills but sometimes inhibiting spontaneous speaking due to anxiety and over-monitoring. Socio-emotional factors, including motivation and confidence levels, significantly affect progress: children typically thrive in playful, low-anxiety environments, while adults frequently benefit from structured, goal-oriented instruction aligned with career or educational aspirations. The paper further discusses the role of first language (L1) transfer, demonstrating how adults’ analytical reliance on L1 frameworks can both facilitate and hinder English fluency. Ultimately, the paper advocates age-appropriate methodologies that blend both communicative and explicit approaches, acknowledging individual variation within each group. Understanding these differences empowers educators, curriculum developers, and policymakers to optimize language-learning environments and outcomes for learners of all ages.

Second Language Acquisition (SLA), Critical Period Hypothesis (CPH), Child Learners, Adult Learners

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