Cross-Linguistic Influence in Third-Language Phonological Acquisition: A Systematic Mapping Review of Empirical Research, 2010-2026

Abstract

Research on third-language (L3) phonological acquisition has grown considerably, but the evidence remains dispersed across language combinations, phonological domains, methods, and theoretical traditions. This systematic mapping review synthesizes a verified corpus of 47 empirical studies published between 2010 and 2026 and distinguishes them from 16 Arab-world and Moroccan publications retained for regional contextualization. The corpus was assembled through focused bibliographic searching, publisher and DOI verification, and backward and forward citation chaining from major reviews of L3 transfer and phonology. Studies were coded for publication period, geographical context, language constellation, phonological domain, method, theoretical orientation, and proposed source of cross-linguistic influence. The mapping shows that research is strongly concentrated in European contexts and in production-oriented studies of consonants, stops, and voice onset time, whereas vowels, stress, prosody, perception-based designs, and longitudinal work remain comparatively limited. Only two core studies directly represented North-African or Arabic-speaking multilingual contexts, and none focused specifically on Moroccan or Amazigh-speaking L3 learners. The evidence does not support a single universal source of transfer; rather, L1, L2, heritage-language, proficiency-based, and property-specific effects are foregrounded across different studies. No confirmed core study explicitly applied Optimality Theory, although OT appears in regional pronunciation research. The review argues for more geographically diverse, theoretically explicit, perception-production, longitudinal, and vowel-focused L3 phonology research, with Moroccan multilingualism offering a particularly valuable testing ground for future work.