NLP (Natural Language Processing) is a subfield of AI that deals with understanding and generating human language. NLP is used in machine learning in a variety of ways, such as text classification, text summarization, sentiment analysis, language translation, and question answering.
An example of NLP in machine learning is text classification. This is a process of categorizing text into predefined classes. For example, a machine learning model could be trained to classify emails as either spam or not spam. The model would use NLP techniques to analyze the text of the emails and assign them to the appropriate class.