• Cross-language transfer and interlanguage phonology in adult bilinguals: across tasks and languages, native-language phonology and transfer shape L2 pronunciation, with devoicing, partial cue retention, and accent development evident in multiple populations [1], [4], [14], [13], [17], [11], [19].

• Phonological neutralization and obstruents: findings challenge absolute final-voicing contrasts, instead showing incomplete neutralization with subtle cue variation (e.g., vowel length, timing) in final obstruents across languages [6], [5].

• Representations, feature geometry, and production planning: a cluster of works argues that phonology relies on geometry of features, multi-layered representations, and planning-level encoding that guides articulation and error patterns [9], [20], [18], [10].

• Lexical and metrical phonology in theory and pedagogy: core works connect lexical phonology constraints with metrical grids, informing phonological change, acquisition, and teaching, via theory-driven analyses and coursebook treatments [3], [16], [2].