Classification of human- and AI-generated texts for different languages and domains

Chatbots based on large language models (LLMs) like ChatGPT are available to the wide public. These tools can for instance be used by students to generate essays or whole theses from scratch or by rephrasing an existing text. But how does for instance a teacher know whether a text is written by a student or an AI? In this paper, we investigate perplexity, semantic, list lookup, document, error-based, readability, AI feedback and text vector features to classify human-generated and AI-generated texts from the educational domain as well as news articles. We analyze two scenarios: (1) The detection of text generated by AI from scratch, and (2) the detection of text rephrased by AI. Since we assumed that classification is more difficult when the AI has been prompted to create or rephrase the text in a way that a human would not recognize that it was generated or rephrased by an AI, we also investigate this advanced prompting scenario. To train, fine-tune and test the classifiers, we created the Multilingual Human-AI-Generated Text Corpus which contains human-generated, AI-generated and AI-rephrased texts from the educational domain in English, French, German, and Spanish and English texts from the news domain. We demonstrate that the same features can be used for the detection of AI-generated and AI-rephrased texts from the educational domain in all languages and the detection of AI-generated and AI-rephrased news texts. Our best systems significantly outperform GPTZero and ZeroGPT—state-of-the-art systems for the detection of AI-generated text. Our best text rephrasing detection system even outperforms GPTZero by 181.3% relative in F1-score.