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AI-generated, L2 learner, and native German writing: a comparative analysis of linguistic complexity

  • Shengzhou Sun and Yuan Li EMAIL logo
Published/Copyright: October 31, 2025
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Abstract

The development of generative AI presents both opportunities and challenges for language teaching. Understanding the linguistic features of AI-generated texts is essential, as it supports users in engaging with AI critically and appropriately for writing tasks. While existing studies have predominantly focused on English writing, the present study examines German argumentative essays produced by ChatGPT, DeepSeek, L1 speakers, and L2 learners, with a focus on linguistic complexity. The results reveal that AI-generated essays generally exhibit higher linguistic complexity. Specifically, DeepSeek essays demonstrate greater lexical complexity, whereas ChatGPT essays are characterized by more complex syntax. In comparison to human-authored essays, AI-generated essays tend to be more formal, marked by frequent nominalizations and a more extensive use of conjunctions. The findings are further interpreted in light of prior research and the underlying mechanisms of generative AI. Based on these results, pedagogical implications for foreign language writing instruction are proposed.


Corresponding author: Yuan Li, Institute of German Studies, Zhejiang University, 866 Yuhangtang Road, Xihu District, Hangzhou, 310058, P.R. China, E-mail:

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Published Online: 2025-10-31

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