Data Science

Natural Language Generation (NLG): A Comprehensive Guide

Published: 17th August, 2023

Harshini Bhat

Data Science Consultant at almaBetter

Learn how Machine Learning powers Natural Language Generation (NLG), enabling AI systems to generate human-like language for chatbots and virtual assistants.

Natural Language Generation (NLG) is a subfield of artificial intelligence (AI) that focuses on the generation of human-like language. NLG has gained significant attention in recent years, as it plays a vital role in various applications such as chatbots, virtual assistants, automated report writing, content generation, and more like ChatGPT, BARD etc.. At the heart of NLG lies Machine Learning, enabling computers to understand and generate coherent and contextually appropriate text. In this article, we will explore the intersection of Machine Learning and NLG and delve into its key components and applications.

Understanding Natural Language Generation

Natural Language Generation in AI is focused on the process of converting structured data or information into human-readable text. It aims to generate text that is indistinguishable from what a human might produce. NLG systems leverage computational algorithms and techniques to analyze data and generate natural language output. These systems make use of Machine Learning to learn patterns, context, and relationships within the data, enabling them to generate meaningful and coherent text.

How does NLG Work?

NLG is a multi-stage process, with each step further refining the data being used to produce content with natural-sounding language. The six stages of NLG are as follows:

  1. Content analysis. Data is filtered to determine what should be included in the content produced at the end of the process. This stage includes identifying the main topics in the source document and the relationships between them.
  2. Data understanding. The data is interpreted, patterns are identified and it's put into context. Machine Learning is often used at this stage.
  3. Document structuring. A document plan is created and a narrative structure is chosen based on the type of data being interpreted.
  4. Sentence aggregation. Relevant sentences or parts of sentences are combined in ways that accurately summarize the topic.
  5. Grammatical structuring. Grammatical rules are applied to generate natural-sounding text. The program deduces the syntactical structure of the sentence. It then uses this information to rewrite the sentence in a grammatically correct manner.
  6. Language presentation. The final output is generated based on a template or format the user or programmer has selected.

How is NLG Used?

Natural language generation is being used in an array of ways. Some of the many uses include the following:

  • generating the responses of chatbots and voice assistants such as Google's Alexa and Apple's Siri;
  • converting financial reports and other types of business data into easily understood content for employees and customers;
  • automating lead nurturing email, messaging and chat responses;
  • personalizing responses to customer emails and messages;
  • generating and personalizing scripts used by customer service representatives;
  • aggregating and summarizing news reports;
  • reporting on the status of internet of things devices; and
  • creating product descriptions for e-commerce webpages and customer messaging.

NLG vs. NLU vs. NLP

Natural Language Processing is an umbrella term that refers to the use of computers to understand human language in both written and verbal forms. NLP is built on a framework of rules and components, and it converts unstructured data into a structured data format.

NLP encompasses both NLG and NLU, which have the following distinct, but related capabilities:

  • NLU refers to the ability of a computer to use syntactic and semantic analysis to determine the meaning of text or speech.
  • NLG enables computing devices to generate text and speech from data input.

Chatbots and "suggested text" features in email clients, such as Gmail's Smart Compose, are examples of applications that use both NLU and NLG. Natural language understanding lets a computer understand the meaning of the user's input, and natural language generation provides the text or speech response in a way the user can understand.

Machine Learning in Natural Language Generation

Machine learning forms the foundation of NLG systems by providing the ability to learn from data and make predictions or generate text based on patterns and relationships found within that data. The key components of Machine Learning in NLG include:

Data Preprocessing: NLG models require high-quality and well-structured data as input. Preprocessing involves cleaning and transforming the data to make it suitable for training the Machine Learning algorithms. Techniques such as tokenization, stemming, and lemmatization are applied to enhance the quality of the data.

Training Data Selection: NLG models learn from examples, and the selection of appropriate training data is crucial. A diverse and representative dataset helps the Machine Learning algorithms generalize patterns and produce more accurate and contextually relevant text. Additionally, annotated datasets, where human-generated text is paired with corresponding input data, are valuable resources for training NLG models.

Feature Extraction: Feature extraction involves transforming raw data into a format that is suitable for Machine Learning algorithms. In NLG, features can include syntactic structures, semantic relationships, sentiment analysis, and topic modeling, among others. These features capture the essential information required for generating coherent and contextually appropriate text.

Model Selection and Training: Various Machine Learning algorithms can be applied to NLG tasks, including sequence-to-sequence models, recurrent neural networks (RNNs), transformers, and deep learning architectures. These models are trained on the annotated datasets, where they learn to map input data to the desired output text. The training process involves optimizing the model's parameters using techniques such as backpropagation and gradient descent.

Applications of NLG in AI

NLG finds applications in a wide range of domains, including:

Automated Report Generation: NLG systems can analyze large volumes of data, such as financial reports or business analytics, and generate comprehensive, human-readable reports. This eliminates the need for manual report writing, saving time and effort.

Virtual Assistants and Chatbots: NLG powers conversational agents by generating natural language responses to user queries or requests. These systems can understand user intent, extract relevant information, and provide contextually appropriate and coherent responses.

Content Generation: NLG can automate content creation for news articles, product descriptions, social media posts, and more. It can generate personalized content tailored to specific audiences, providing a scalable solution for content creation.

Language Tutoring: NLG can assist language learners by generating exercises, quizzes, and interactive lessons. It can provide real-time feedback and adapt the content based on the learner's proficiency level and progress.


Machine Learning plays a pivotal role in advancing the capabilities of Natural Language Generation. By leveraging the power of Machine Learning algorithms, NLG systems can analyze data, learn patterns, and generate human-like text that is contextually relevant and coherent. The applications of NLG span various domains, revolutionizing the way we communicate with AI systems and automating tasks that traditionally required human intervention. As Machine Learning continues to evolve, NLG will become even more sophisticated, bridging the gap between AI-generated and human-generated language.

Frequently asked Questions

Q1.What is the role of machine learning in Natural Language Generation (NLG)?

Ans: Machine learning is crucial in NLG as it allows computers to analyze data, learn patterns, and generate coherent and contextually appropriate human-like text. It enables NLG systems to understand and generate natural language output.

Q2:What are the applications of NLG in AI?

Ans: NLG has a wide range of applications, including automated report generation, virtual assistants and chatbots, content generation, and language tutoring. It revolutionizes communication with AI systems and automates tasks that previously required human intervention.

Q3:How does NLG differ from NLU and NLP?

Ans:NLG focuses on generating human-like text, while Natural Language Understanding (NLU) involves understanding the meaning of text or speech. Natural Language Processing (NLP) is a broader term encompassing both NLG and NLU, where NLP converts unstructured data into structured data using rules and components.

Related Articles

Top Tutorials

Made with heartin Bengaluru, India
  • Official Address
  • 4th floor, 133/2, Janardhan Towers, Residency Road, Bengaluru, Karnataka, 560025
  • Communication Address
  • 4th floor, 315 Work Avenue, Siddhivinayak Tower, 152, 1st Cross Rd., 1st Block, Koramangala, Bengaluru, Karnataka, 560034
  • Follow Us
  • facebookinstagramlinkedintwitteryoutubetelegram

© 2024 AlmaBetter