Diachronic changes in syntactic complexity of science research articles: a comparative study of medicine and mechanical engineering

The present study complements previous diachronic investigations of linguistic features in English academic writing from a syntactic complexity perspective. Specifically, it investigated diachronic trends in the syntactic complexity of science research articles (RAs) over a time span of 50 years. Based on a corpus of 960 RAs published between 1970 and 2020 in Medicine and Mechanical Engineering, the syntactic complexity of texts from the two disciplines was assessed using multiple indices of global, clausal, and phrasal levels and was compared across the examined years. The findings show that the two disciplines participated to varying degrees in changes in syntactic complexity. Both disciplines displayed an uptrend in global and phrasal complexity, but the trends were more pronounced in Medicine. Mechanical Engineering showed a downtrend in clausal complexity, while Medicine changed little at this level. In addition, significant differences were found between the two disciplines in syntactic complexity indices at most time points, and the differences were more important in recent years than in earlier years. Possible explanations for these changes and variations in the syntactic complexity of science RAs over time were offered.