Natural Language Processing (NLP), Natural Language Understanding (NLU), and Natural Language Generation (NLG) are closely related topics but are distinct from one another. These are related because they deal with the human language. These are all natural language topics because they are addressing how humans naturally speak with one another rather than how a computer may speak to another computer. All three components play a part just as they do in the human experience of conversation. In our normal conversation, we not only speak words in a certain way, but we also try to understand other persons’ words as we listen to them. Further, when we answer, we are generating speech for our response.

What Is NLP?

Natural Language Processing (NLP) is a branch of Artificial Intelligence (AI). Besides AI, it is a product of disciplines such as computer science, linguistics, and data science. These are used to enable computers to understand human language as written or spoken. NLP especially uses the technologies of Machine Learning (ML) and deep learning to be enabled to accomplish such things as language translations or answering questions.

NLP processes the unstructured data of human language, spoken or written, by restructuring it into digital data more easily understandable to intelligent computer programs. This is done by detecting named entities and word patterns and looking at the root forms of words.

What Is NLU?

Natural Language Understanding (NLU) is a subset of NLP. It is employed by NLP to perform the part of understanding the language that NLP is processing. For example, our general thinking is like the NLP part, and our understanding of what we hear or read is like the NLU part of the process.

Without getting too deep, this NLU part does an analysis of semantics and syntaxes of text and speech. It tries to discern the meaning of what is received. Analyzing the syntax of a sentence helps us understand the grammatical structure: what is being said. Think of the phrase, “Are you asking me or telling me?” Analyzing the semantics of a sentence helps us understand the intended sense: what is being implied. Think of the phrase, “What are you implying by that question?”

What Is NLG?

Natural Language Generation (NLG) is another subset of NLP. It does the function of providing output language in response to the input language. It does the answering in written language understandable to humans. This response can also be converted to spoken words by using text-to-speech services. Originally, the NLG component simply performed a method of filling in blanks according to a template in response to key phrases or questions. But NLG has evolved into a more dynamic process by using such services as recurrent neural networks, transformers, and hidden Markov chains. A hidden Markov model is a statistical method to guess what will be said based on some other known parameters.


NLP and the companion components of NLU and NLG are a group of significant Artificial Intelligence (AI) software technologies. They have revolutionized the way digital technology serves human intelligence. These technologies enable computers to interact with people in a much more human-like way. They make the services that computers provide much more accessible for the greatest number of average users possible.

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