
You’ve used a large language model even if you’ve never heard the term — it’s the technology behind ChatGPT, Google’s Gemini, and the AI writing features built into apps you already use. But what is a large language model exactly, and how does it actually work?
This plain-English guide explains what LLMs are, how they’re trained, what they’re genuinely good (and bad) at, the main models to know in 2026, and how to use them safely — no computer-science background required.



