1.0 What is an LLM? A Guide to Large Language Models in NLP

Published on: 2024-09-02 Last updated on: 2026-08-24 Version: 19
1.0 What is an LLM? A Guide to Large Language Models in NLP

1.0 What is LLM?

LLMs (Large Language Models) are groundbreaking technologies in the field of natural language processing (NLP). Trained on massive datasets, these models possess the ability to understand context and generate natural, human-like text. This article provides a foundational understanding of LLMs, their roles, and how they differ from traditional machine learning models.

One line: An LLM is a transformer network with hundreds of millions to trillions of parameters, pre-trained on huge text corpora so it can handle many NLP tasks with the same base weights.
What makes an LLM Massive text datasets web, books, code Transformer architecture self-attention layers Billions of parameters learned weights Pre-training + fine-tune next-token loss Large Language Model general-purpose text generator
Figure 1 — Four ingredients combine into a single general-purpose LLM.

1.1 Definition and Overview

LLMs are advanced language models containing hundreds of millions to trillions of parameters. These parameters, trained on vast text datasets, allow LLMs to comprehend context and generate grammatically accurate and coherent sentences. Their ability to emulate human-like understanding makes them versatile across numerous NLP applications.

1.2 Role in Natural Language Processing

LLMs excel in a variety of NLP tasks, including translation, summarization, question answering, and text generation. By leveraging their advanced contextual understanding, these models outperform traditional rule-based systems, offering more accurate, flexible, and scalable solutions.

1.3 Differences from Machine Learning

Traditional machine learning models are typically specialized for a single task, requiring retraining for new applications. In contrast, LLMs are general-purpose models that can be adapted to various tasks after initial training. This versatility, driven by techniques such as transfer learning, sets LLMs apart. However, their computational demands far exceed those of traditional models.

Dimension Traditional NLP / ML LLM
ScopeOne model per task (classifier, translator, tagger…).One base model, many tasks via prompting or fine-tuning.
Feature engineeringHand-crafted features, rules, lexicons.Raw tokens; representations learned end-to-end.
Data need per taskThousands of labeled examples for each new task.Few-shot or zero-shot often works out of the box.
Compute footprintModest — trains on a laptop or single GPU.Large — pre-training needs GPU/TPU clusters.
Output styleDiscrete labels or fixed templates.Free-form natural language.
Table 1 — Where LLMs depart from the traditional per-task NLP pipeline.

In the next section, "Definition and Overview of LLM", we’ll provide a deeper dive into the components of LLMs. This includes their structure, scalability, and how they are trained to perform advanced NLP tasks.


This article is adapted from the book “A Guide to LLMs (Large Language Models): Understanding the Foundations of Generative AI.” The full version—with complete explanations, and examples—is available on Amazon Kindle or in print.

You can also browse the full index of topics online here: LLM Tutorial – Introduction, Basics, and Applications .


SHO
SHO
CTO of Receipt Roller Inc., he builds innovative AI solutions and writes to make large language models more understandable, sharing both practical uses and behind-the-scenes insights.

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