Poznań, Polonia
This study investigates how learning L2, L3, or L4 Germanic in a non-immersed, instructed context influences L1 Polish word order. It focuses on three word-order patterns: adverb placement, verb placement with adverbial fronting, and verb placement with object fronting. While these constituents have fixed positions in Germanic languages, their ordering in Polish is determined by pragmatic and semantic factors. The structures additionally differ in frequency in Ln and degree of optionality in L1, providing a productive setting for exploring factors driving cross-linguistic influence. The study reports data from an offline acceptability judgement task, collected from 228 participants divided into four groups: Polish-English bilinguals (n = 27), Polish-English-German trilinguals (n = 40), Polish-English-Scandinavian trilinguals (n = 74), and Polish-English-German-Scandinavian quadrilinguals (n = 87). Analysis using linear mixed-effects models reveals regressive cross-linguistic influence, which is most apparent in the quadrilingual group, highlighting the combined impact of two non-native languages working in parallel. The influence is driven by increasing proficiency in Ln and manifests differently across structures, underscoring the importance of frequency in Ln input and the degree of optionality that the language undergoing change allows. This provides novel evidence of the regressive influence of non-native languages on L1 syntax in non-immersed contexts.