<![CDATA[This study aims to investigate the dynamics of syntactic and phonological acquisition in a three-year-old child through an integrative psycholinguistic perspective. Using a mixed-method design, the data were collected through longitudinal observation over one and a half months employing the participant observation technique on eleven spontaneous utterances produced by a native Indonesian-speaking child. The analysis was conducted quantitatively through the frequency distribution of sentence patterns and the calculation of Mean Length of Utterance (MLU), as well as qualitatively using the Functional Grammar framework validated through expert triangulation. The results indicate the dominance of the S+P+O structure (27.3%) with an MLU value of 4.27 morphemes, suggesting a stable transition from telegraphic speech to differentiated clauses. Simultaneously, phonological processes such as stopping, deletion, and assimilation were identified as adaptive cognitive-articulatory strategies that did not interfere with thematic role mapping or pragmatic coherence. This study concludes that phonological simplification and syntactic-semantic expansion operate in an integrated manner within limited processing capacity, confirming that grammatical development is driven by communicative needs before articulatory refinement is fully achieved. These findings imply the importance of holistic early language assessment, utterance-function-based intervention, and caregiver scaffolding strategies that are responsive to children’s communicative intentions.]]>
