L2 English interference in Chinese learners of L3 Portuguese: a corpus-based analysis of transfer-induced errors

Abstract This study investigates English-mediated cross-linguistic influence in Chinese learners of Portuguese as a foreign language. Using a corpus of forty written compositions across CEFR levels A1–B2, each text was manually annotated for four interference types, namely lexical, ortho-phonological, grammatical, and pragmatic/discourse, following a predefined coding scheme. Overall interference frequency declined from 4.93 per 100 tokens at A1 to 1.56 at B2, representing a 68.3% reduction, with 95% confidence intervals confirming the downward trend. Analysis of error composition revealed significant developmental patterns (χ 2 = 19.752, p = 0.020): grammatical interference predominated at lower levels, while lexical interference became increasingly salient at higher levels; ortho-phonological and pragmatic/discourse interference remained relatively stable. These results indicate property-sensitive L3 transfer dynamics, highlighting the developmental shift from grammatical to lexical interference, and offer practical implications for proficiency-sensitive Portuguese as a foreign language instruction.