Abstract：Using a corpus of historical vernacular Chinese as data, this study presents a diachronic investigation into the macroscopic changes of modern Chinese in structural complexity (SC) over the past century. Specifically, the study examines the relationship between diachronic changes of SC and sentence segment length (SSL) and assesses SC changes and their motivating factors by using colligation and dependency distance measures. The study yields the following four findings. 1) Over the past century, SC in Chinese has exhibited an overall increase, with its increase occurring most noticeably during the 1920s and 1930s; 2) Changes in SC have varied across genres, with a small change found in literary texts, while greatest change observed in academic texts; 3) Parallel to changes in SC, similar change patterns have occurred with SSL, with the SSL changes being a strong predicator of those of SC; 4) The diachronic analysis of colligations shows that colligations containing adverbs can form sentence segments with a lower complexity, which are used mostly as discourse markers in literary texts, while colligations containing the particle “de” (的) are found mostly in incomplete expressions used to form complex structures in academic texts; 5) SC measured by dependency distance has also displayed a diachronic increase, with the greatest increase also found in academic texts. The study suggests that while it is logical to study changes in modern Chinese by examining spoken and written languages as a dichotomy, a genre-based account of change may enable us to present a systematic description of the variations in the extent of SC changes across genres. As have been shown in this study, SC changes in modern Chinese have exhibited the following hierarchical pattern: academic writings > general texts > news > novels.
Key words: modern Chinese; diachronic corpus; structural complexity; sentence segment length
