Phonological acquisition in adulthood presents a distinct constellation of cognitive challenges, often shaped by intrinsic limitations of working memory, attentional control, and overall cognitive load. This article explores how cognitive load interacts with the processes through which adult learners perceive, store, and produce phonological features in a second language (L2). Drawing on contemporary psycholinguistics, cognitive science, and second language acquisition research, the study argues that adult phonological development is not merely constrained by biological maturation but, more importantly, by how cognitive resources are distributed during learning. The article highlights the interplay between declarative and procedural memory systems, the impact of attentional bottlenecks on segmental and suprasegmental processing, and the role of explicit instruction in reducing perceptual strain. It concludes by proposing pedagogical strategies designed to reduce cognitive load, enhance phonological processing, and support more efficient L2 sound system acquisition among adults.