How does a large language model like ChatGPT actually generate text?

A large language model like ChatGPT is like a super-smart friend who knows how to write stories by looking at lots of other stories and learning from them.

Imagine you're playing with building blocks, and your friend has seen every tower ever built. When you ask them to build something new, they look at all the towers they’ve seen before, think about what makes sense, and then pick the best blocks to make a new tower, just like that!

ChatGPT uses patterns it has learned from reading lots of text. Think of it as having read every book in a huge library, millions of books! When you start typing a sentence, ChatGPT looks at what you’ve written so far and thinks: “What comes next?” It checks the patterns it knows best and chooses the most likely words to complete the thought.

It's like playing a game where you say part of a sentence, and your friend guesses the rest. The more sentences ChatGPT has seen, the better it gets at guessing, and that’s how it can write full paragraphs or even whole stories!