This study examined the trajectories of the multi-word constructions (MWCs) in 98 advanced second language (L2) learners during their first-year at an English-medium university in a non-English-speaking country, using linear mixed-effects modelling, over one academic year. In addition, this study traced the academic reading input that L2 learners received at university, and it was investigated whether the frequency and dispersion of the MWCs in the input corpus would predict the frequencies of MWCs in L2 writers’ essays. The findings revealed variations in the frequencies of different functional and structural categories of MWCs over time. This study provides empirical evidence for the effects of both frequency and dispersion of MWCs in the input corpus on the frequency of MWCs in L2 writers’ essays, underscoring the importance of both frequency and dispersion in learning MWCs and the reciprocity of academic reading and writing. The findings have significant implications for usage-based approaches to language learning, modelling MWCs in L2 academic writing, and L2 materials design for teaching academic writing.

这项研究使用线性混合效应模型研究了98个高级第二语言（L2）学习者在非英语国家/地区的英语中等大学一年级时的多词构造（MWC）的轨迹，超过一学年。此外，本研究追踪了大学二年级学习者所接受的学术阅读输入，并调查了输入语料库中MWC的频率和分布是否可以预测L2作者论文中MWC的频率。研究结果揭示了随时间变化的MWC的不同功能和结构类别的频率变化。这项研究提供了经验证据，证明了输入语料库中MWC的频率和离散度对二语作者论文中MWC的频率的影响，强调频率和分散性在学习MWC中的重要性以及学术阅读和写作的互惠性。这些发现对于基于使用的语言学习方法，在L2学术写作中对MWC进行建模以及在学术写作中进行L2材料设计具有重要意义。