Which aspect of NLP involves extracting key phrases from a text?

The aspect of NLP that involves extracting key phrases from a text is text analytics. Text analytics encompasses various techniques used to process and analyze textual data, enabling the extraction of important information, concepts, or phrases that can help in understanding the content's main points. This process may include techniques such as summarization, keyword extraction, and identifying relationships and patterns within the text.

Named entity recognition typically focuses on identifying and classifying named entities (such as people, organizations, locations) within the text, which is a more specific task than general key phrase extraction. Sentiment analysis assesses the emotional tone or sentiment behind a body of text, classifying it as positive, negative, or neutral. Language understanding pertains to comprehending and interpreting the meaning of the language, which is broader than just extracting key phrases and often involves language models and contextual understanding.

Thus, text analytics is the correct aspect related to the task of extracting key phrases, as it addresses the extraction and analysis of key information within text data.