What Is an LLM and How Is It Trained? Large Language Models (LLMs) are the powerhouses behind modern AI chatbots, search assistants, and automated content generators. They work by predicting the next most likely word in a sequence based on extensive training data. These models are trained on billions of words from books, articles, websites, and other written materials, absorbing grammar, context, and meaning at an unprecedented scale. However, what’s surprising—and honestly a little unsettling—is that we don’t actually know exactly how LLMs work internally.