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Natural Language Generation: Definition and Examples

Natural Language Generation (NLG) is the branch of artificial intelligence that enables machines to automatically produce human language text from structured data or instructions.

Full definition

Natural Language Generation (NLG) refers to the set of AI techniques that allow a computer system to produce text understandable by a human being. Unlike Natural Language Understanding (NLU), which aims to understand language, NLG focuses on producing coherent, grammatically correct, and contextually relevant text.

Historically, early NLG systems relied on templates (predefined models) and manually coded linguistic rules. These approaches produced rigid and predictable texts, such as automated weather bulletins or financial summaries. The advent of neural networks, then transformers, radically transformed the field: language models like GPT or Claude are capable of generating fluid, nuanced, and creative text from a simple natural language instruction.

In prompt engineering, NLG is at the heart of every interaction with an LLM. Each response generated by the model is an act of NLG. The quality of the produced text directly depends on the quality of the prompt: a precise, well-structured, and contextualized prompt guides the model toward more relevant and useful generation.

Modern applications of NLG span an immense spectrum: writing articles, generating code, creating chatbot dialogues, machine translation, document summarization, personalizing marketing content, and much more. Today, it is one of the most visible and widely used capabilities of generative artificial intelligence.

Etymology

The term 'Natural Language Generation' emerged in the 1970s-1980s within the natural language processing (NLP) research community. It combines 'natural language' (as opposed to formal languages like programming languages) and 'generation' (production, creation). The expression became established to distinguish this discipline from 'Natural Language Understanding', its counterpart dedicated to comprehension.

Concrete examples

Automatic drafting of a meeting summary from raw notes

Here are the notes taken during our team meeting. Generate a structured report with decisions made, actions to take, and identified responsible persons.

Generating product descriptions for an e-commerce site

From this technical sheet (material: organic cotton, color: navy blue, size: S to XL), write an engaging product description of 100 words for our online store, warm and professional tone.

Creating narrative reports from numerical data

Here are the quarterly KPIs in table format. Write an analysis paragraph for management highlighting the main trends and points of attention.

Practical usage

In prompt engineering, mastering the principles of NLG allows you to formulate instructions that effectively guide the model toward the desired type of text. Specifying the tone, format, length, and target audience in your prompts significantly improves generation quality. Consider providing examples of the expected style (few-shot prompting) to anchor the model in the desired linguistic register.

Related concepts

Natural Language ProcessingNatural Language UnderstandingLarge Language ModelText-to-Text Generation

FAQ

What is the difference between NLG and NLU?
NLU (Natural Language Understanding) enables a machine to understand and interpret human text, while NLG (Natural Language Generation) enables it to produce text. They are two complementary sides of natural language processing: NLU analyzes, NLG creates. Modern LLMs combine both capabilities in a single model.
Can NLG-generated text be detected as AI-written?
Detection tools exist but remain imperfect, especially with recent models that produce very natural text. Detectability depends on the model used, prompt quality, and post-processing applied. In practice, AI-generated text that has been reworked by a human becomes very difficult to distinguish from fully human-written text.
How can I improve the quality of text generated by an LLM?
Three main levers: specify the context and objective in the prompt (audience, tone, format), provide examples of the expected result (few-shot prompting), and iterate by refining your instructions. Asking the model to structure its response (headings, lists, paragraphs) and to respect specific constraints (length, vocabulary) also makes it easier to obtain more usable results.

See also

How to use this prompt

  1. Copy the prompt with the button above.
  2. Paste it into ChatGPT, Claude or your favorite AI assistant.
  3. Replace the bracketed variables with your details, then refine the result.

About Prompt Guide

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