Welcome to the Course

Welcome to the first lesson of Mastering Communication with AI Language Models! Large Language Models (LLMs) like ChatGPT are transforming how we interact with technology. But how do they work, and why do they sometimes sound so human? Let's break it down in simple terms, while keeping an eye on their quirks and limitations.

What Are Large Language Models?

Large Language Models are AI systems trained on massive amounts of text data — like books, articles, and websites. Their job is to predict the next word in a sentence, enabling them to generate coherent text. Think of them as supercharged autocomplete tools. For example:

  • If you type, "The sky is…," an LLM can predict blue or filled with stars, depending on context.

Unlike traditional applications (e.g., calculators or weather apps) that follow strict rules, LLMs learn patterns from data. This makes them flexible, but it also means they can sometimes produce unexpected or factually incorrect responses (hallucinations).

Popular LLMs and How to Choose the Right One

All LLMs can hallucinate and their quality depends on specific model/version and settings. It would be fare to say that modern LLMs are close to each other in their performance.

The practical differences are mostly about workflow fit: tool integrations, long-context performance, writing style, search/citations, and whether you can run it privately.

OptionPick it when you need…What it’s notably good atMain tradeoff
ChatGPT (OpenAI)A do-everything assistantStrong coding + general writing; lots of built-in tooling and integrationsLess “citation-first” by default; may require extra steps for sourced research
Claude (Anthropic)Heavy reading + clean writingExcellent long-document summarization and polished toneOften more cautious with certain requests
Google GeminiGoogle ecosystem + multimodalTight integration with Google tools; strong multimodal workflowsBest experience is often inside Google’s stack
PerplexityResearch with sourcesSearch-native answers with citations and quick comparisonsBest for “find + summarize,” not always best for creative drafting
Llama / Mistral (open-weight)Privacy/controlRun locally/on-prem; customize and control data flowYou own setup/ops and performance tuning

Please note that the AI field is rapidly evolving, and new developments may have emerged since this information was compiled.

How LLMs "Understand" and Generate Text

LLMs don't truly understand language in a human sense. Instead:

  1. Training Phase: They analyze billions of sentences to learn word relationships (e.g., king relates to queen like man relates to woman).
  2. Prediction Phase: When you type a prompt, they predict the most likely next words based on these patterns.

Why Do They Sometimes Get It Wrong?
They rely on patterns in their training data rather than genuine comprehension or intent. This can lead to bizarre or nonsensical responses when the data patterns aren't clear — or when they try to "fill in the gaps" with guesses.

Example:
Ask, "How do I make a cake?" and the LLM will combine commonly seen recipe terms — like flour, sugar, bake — to form a plausible set of instructions. However, it's copying patterns, not recalling a specific recipe it "remembers."

Key Takeaways
  • LLMs are powerful pattern recognizers, not deep thinkers.
  • They can struggle with real-time information unless explicitly connected to live data.
  • Be aware of biases or hallucinations — they come from gaps or biases in the training data.
  • The clearer your prompt, the better your chances of getting a high-quality response.
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