A PRISMA-based systematic review of bilingual conceptual representation in typologically diverse language pairs

Abstract

Understanding how linguistic distance influences bilingual conceptual representation is critical for refining models of bilingual processing. However, existing research has predominantly focused on Indo-European or typologically similar language pairs, limiting theoretical generalisability. This systematic review explores cross-linguistic facilitation and interference effects in bilingual semantic processing across two typologically distinct language pairs to examine the role of linguistic distance and its implications for conceptual representation models. Adhering to the PRISMA 2020 framework, a comprehensive literature search was conducted to identify studies investigating bilingual conceptual and semantic processing. Findings suggest that linguistic distance modulates cross-linguistic interaction. Spanish-English bilinguals exhibited greater facilitation effects, likely due to phonological and orthographic overlap, whereas Chinese-English bilinguals showed stronger interference effects and greater reliance on L1 conceptual mediation. The results offer partial support for several bilingual processing models, including the Revised Hierarchical Model (RHM), Distributed Conceptual Feature Model (DCFM), and BIA+ model. However, no single model fully accounts for the differential effects of linguistic distance. The review also identifies methodological gaps and inconsistencies across studies, particularly in participant profiling, study design, and task selection. In response, the SCOPE-BI framework (Systematic Conceptual and Operational Protocol for Enhancing Bilingual Investigation) is proposed to promote standardisation, comparability, and diversity in bilingualism research. By incorporating open science practices—such as detailed participant profiling, monolingual control groups, standardised tasks, preregistration, and data sharing. SCOPE-BI provides a structured approach for evaluating and refining models of bilingual conceptual representation.