Beyond Word Counts: A Corpus-Based Analysis of Lexical and Syntactic Patterns in Undergraduate Academic Essays

Abstract Academic writing requires learners to demonstrate lexical sophistication, syntactic complexity, and adherence to disciplinary conventions. However, many undergraduate students continue to experience difficulties in producing writing that reflects the linguistic features expected in academic discourse. This study employed a descriptive corpus-based research design to examine the lexical and syntactic characteristics of academic essays written by fourth-year Bachelor of Arts in English Language Studies (BAELS) students at J.H. Cerilles State College. A learner corpus consisting of forty academic essays was analyzed using AntConc and Sketch Engine to investigate word frequency, Academic Word List (AWL) coverage, collocational patterns, sentence structures, and syntactic complexity. The findings revealed a strong reliance on high-frequency general vocabulary, limited use of academic lexis, and frequent dependence on predictable collocations. Syntactic analysis likewise showed a predominance of simple sentence structures, limited subordination, and relatively low syntactic complexity compared with established academic writing norms. These linguistic patterns indicate that although students demonstrate functional writing competence, their essays fall short of the lexical precision and structural sophistication expected in academic writing. The study highlights the value of corpus-based analysis in identifying recurring linguistic features that may not be readily apparent through conventional writing assessment. The findings further support the integration of corpus-informed pedagogy and Data-Driven Learning (DDL) strategies into English for Academic Purposes (EAP) instruction to strengthen academic vocabulary development, improve syntactic variety, and enhance overall writing proficiency among undergraduate learners. Keywords: Academic writing; corpus linguistics; Data-Driven Learning; English for Academic Purposes; lexical patterns; syntactic complexity