NEUROBIOLOGICAL INSIGHTS INTO THE FACULTY OF LANGUAGE WITHIN BIOLINGUISTICS

In the field of biolinguistics, theoretical models treating language as a biological system have advanced rapidly, yet the neurobiological evidence underpinning these models has lagged behind, creating a significant gap between theory and data. This study bridges the theoretical framework of biolinguistics with empirical neurobiological evidence to examine the neural foundations of the faculty of language, both in its broad (FLB) and narrow (FLN) senses. Drawing on recent neurobiological findings, the study demonstrates that the modular architecture of FLB—comprising phonological-phonetic, syntactic, semantic, and pragmatic modules—is instantiated in distinct yet dynamically interacting neural circuits. Notably, the left inferior frontal gyrus (IFG) and the posterior superior temporal gyrus (pSTG) play central roles in syntactic computation, while the left superior and middle temporal gyri are primarily involved in semantic computation. Evidence from comprehension studies further highlights that syntactic computations may continue beyond the point of initial phrase construction, indicating that syntactic computations are not necessarily complete once their outputs are transmitted to other modules (semantic, pragmatic, phonological-phonetic modules). Regarding FLN, the core syntactic operation merge is shown to be implemented in the BA 44 of the left IFG as the neural locus of external merge. While some cross-species studies suggest merge-like abilities in non-humans, the neurobiological specificity of merge remains uniquely human. Internal merge, responsible for syntactic movement, has not yet been systematically investigated in terms of its neural underpinnings; however, a review of neuroimaging studies involving syntactic displacement suggests that internal merge engages overlapping regions in the IFG, indicating a shared but functionally distinct neural basis. This study affirms the biological grounding of the faculty of language and argues for a more integrative empirical agenda in biolinguistics—one that combines theoretical precision with neuroscientific rigor to uncover the architecture of language.