Final answer:
The field of communication research that focuses on how language is used to affect the beliefs of audiences is known as rhetoric, which involves the study of persuasive speech and writing within different communicative situations.
Step-by-step explanation:
The field of communication research that examines how people use words to compel audiences to change or solidify their beliefs is best described by the term rhetoric. Rhetoric is the art of persuasive speaking or writing, with a rich history dating back to ancient Greece and philosophers like Socrates and Aristotle. The study of rhetoric involves understanding how language can be crafted in order to persuade an audience to take a certain action or adopt a specific viewpoint. This includes analyzing the rhetorical situation, which refers to the conditions in which communication takes place, as well as the people involved in that communication.
Rhetoric is also concerned with the effectiveness of communication, whether through spoken words, written text, or even non-verbal cues such as facial expressions and tone of voice. The analysis of rhetorical strategies is crucial for understanding the intent behind messages and the impact they may have on audiences. With rhetoric's roots in classical education and its ongoing relevance in modern society, it plays a vital role in the study of communication across various platforms, including social media and academic discourse.