Pragmatics refers to the aspect of language that involves the social use of language in various contexts. It encompasses understanding the nuances of communication, such as tone, context, and the meanings that arise from social interactions. This includes knowing how to start and sustain conversations, recognize social cues, and adapt language to suit different situations or audiences.
In contrast, phonology focuses on the sounds of speech and how they are organized in particular languages. Syntax relates to the rules that govern the structure of sentences and how words combine to form meaningful phrases. Semantics deals with the meanings of words and sentences themselves, rather than the social context in which they are used. Therefore, both syntax and semantics are essential for constructing and understanding sentences but do not encompass the social interaction aspect that defines pragmatics. Thus, the correct answer reflects the essential role of pragmatics in social language use.