Non-finite clause use in disciplinary research writing: a formulaic sequence-based functional comparison between expert and student writers

Abstract Non-finite clauses (NFCs), despite their increasingly recognized role in second language (L2) acquisition and academic writing as part of a multidimensional conceptualization of syntactic complexity, have not been analyzed in functional and discipline-specific perspectives. This study addresses this gap by providing a linguistic-descriptive account of NFC use in expert and advanced student English research writing. Using a 2.26-million-word corpus of published research articles and student manuscripts in Agricultural Science, this study profiles the distribution of NFC subtypes and identifies frequent discoursal functions realized by non-finite verb-centered formulaic sequences. The findings reveal significant differences in NFC use across writer groups, with student writers utilizing NFCs less overall and in the majority of structural subtypes. Functional analyses further demonstrate that advanced student writers employed a narrower range of formulaic frames for a narrower range of discoursal functions, highlighting both a reduced lexical repertoire and a rhetorically less sophisticated style, in regard to NFCs. Findings underscore the importance of considering a full range of lexical/phraseological and discourse-functional patterns of clause-level linguistic features, such as NFCs, in order to gain a more pedagogically interpretable understanding of syntactic complexity in L2 and academic writing.