AUSTRALIAN REVIEW OF APPLIED LINGUISTICS, cilt.0, sa.0, ss.1-43, 2026 (ESCI, Scopus)
Lexical errors have a significant impact on the clarity and effectiveness of written communication, and their existence may create serious communication breakdowns. The detection of these infelicities and their possible causes have the potential to illuminate the interlanguage phases of L2 English learners. Over the years, experts have attempted to categorise learner errors, employing various approaches. The current study uses Hemchua and Schmitt’s (2006) taxonomy as the foundational framework, customising it to accommodate the characteristics of the learner corpus under examination. One hundred and thirty-nine undergraduate students in different Turkish universities wrote 244 opinion essays, which underwent error tagging by a team of researchers. The findings indicate that L1 Turkish learners of English make more semantic lexical errors than formal ones. More specifically, the corpus is characterised by prevalent errors in sense relation, style, collocational usage, and L1 transfer. Further analysis suggests that two semantic error types (i.e., confusion of sense relations and stylistic errors) and a formal error type (i.e., formal misselection) significantly influence the overall writing quality in L2 English. The findings are discussed in light of current second language acquisition theories and based on the detected lexical errors and their possible effect on writing quality, leading to several pedagogical conclusions.