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Sreekar Reddy
Sreekar Reddy

Posted on • Originally published at sreekarreddy.com

🧠 LLMs Explained Like You're 5

A very well-read librarian

Day 11 of 149

👉 Full deep-dive with code examples


The Librarian Analogy

Imagine a librarian who has:

  • Read every book in the library
  • Memorized patterns of how language works
  • Can predict what word comes next in a sentence

You ask: "The capital of France is ___"
Librarian: "Paris"

LLMs are librarians trained on huge amounts of text (including lots of internet text).


What LLM Stands For

Large Language Model

  • Large → Billions of parameters (memory)
  • Language → Trained on text
  • Model → Mathematical prediction engine

How They Work (Simply)

LLMs just predict the next word:

Input: "The cat sat on the"
LLM thinks: What word typically follows this?
Output: "mat" (high probability)
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String enough predictions together, and you get:

  • Essays
  • Code
  • Poems
  • Conversations

The Training

To predict well, they learn by:

  1. Feed them LOTS of text (books, Wikipedia, code, websites)
  2. Ask: "Predict the next word"
  3. If wrong, adjust the model
  4. Repeat billions of times

After training, they've learned patterns of language.


Famous LLMs

  • GPT-4 (OpenAI)
  • Claude (Anthropic)
  • Gemini (Google)
  • Llama (Meta)

In One Sentence

LLMs are AI models trained on massive text to predict what comes next, enabling them to write, answer questions, and code.


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