Google last month upgraded its Bard chatbot with a new machine-learning model that can better understand conversational language and compete with OpenAI’s ChatGPT. As Google develops a sequel to that model, it may hold a trump card: YouTube.

The video site, which Google owns, is the single biggest and richest source of imagery, audio and text transcripts on the internet. And Google’s researchers have been using YouTube to develop its next large-language model, Gemini, according to a person with knowledge of the situation. The value of YouTube hasn’t been lost on OpenAI, either: The startup has secretly used data from the site to train some of its artificial intelligence models, said one person with direct knowledge of the effort.