Encyclopedia Britannica and Merriam-Webster filed a lawsuit against OpenAI on Friday, alleging the artificial intelligence company used their copyrighted content without authorization to train its language models.

The publishers claim OpenAI violated the copyright of nearly 100,000 articles by incorporating their content into the training data for its AI systems. According to the lawsuit, OpenAI repeatedly copied content from both companies without obtaining proper permission.

Britannica alleges that OpenAI's GPT-4 model has "memorized" substantial portions of their content and subsequently generates responses that are "substantially similar" to the original copyrighted material. The publishers argue this constitutes copyright infringement on a massive scale.

The lawsuit represents another significant legal challenge facing OpenAI over its training practices. The company has previously faced similar copyright infringement claims from other content creators and publishers who argue their work was used without consent to develop AI capabilities.

Neither OpenAI nor representatives for Encyclopedia Britannica and Merriam-Webster immediately responded to requests for comment about the litigation. The case adds to growing legal scrutiny over how AI companies obtain and use training data for their models.