<b>Structure, Function, and Connectivity in The Multilingual Brain: A Systematic Review of Neurolinguistic Evidence and Implications for Language Education</b>

This research addresses this gap by means of a mixed-methods study that triangulates three independent strands of data: a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) compliant Systematic Literature Review (SLR), a structured survey (N = 14) and a qualitative protocol comprising semi-structured interviews and Focus Group Discussions (FGDs).

The SLR based on 487 records from Scopus, Web of Science, PubMed, and ERIC (2010-2025) identified 33 high-quality peer-reviewed studies evaluated with a binary Quality Assessment Rule (QAR; inter-rater κ = .84). The structured survey utilized the 58-item Neurolinguistic Profile and Performance Assessment Scale (NIPPAS), which operationalized ten neurolinguistically grounded constructs: Executive Control (EC), Metalinguistic Awareness (MA), Structural Language Processing (SLP), Cross-linguistic Connectivity (CLC), Adaptive Communication (AC), Metacognitive Monitoring (MM), Multilingual Memory (MEM), Neuroplasticity Indicators (NPI), Sociocultural Integration (SCI), and Language Acquisition Efficiency (LAE).