Contextualization in sociolinguistics refers to the use of language (both spoken language and body language) to signal relevant aspects of an interaction or communicative situation. This may include clues to who is talking, their relationship, where the conversation is occurring, and much more. These clues can be drawn from how the language is being used, what type of language is being used (formal versus informal), and the participants tone of voice (Andersen and Risør 2014). Contextualization includes verbal and non-verbal clues of things such as the power dynamic or the situation apparent from a conversation being analyzed or participated in. These clues are referred to as "contextualization cues". Contextualization cues are both verbal and non-verbal signs that language speakers use and language listeners hear that give clues into relationships, the situation, and the environment of the conversation (Ishida 2006). An example of contextualization in academia is the work of Basil Bernstein (1990 [1971]). Bernstein describes the contextualization of scientific knowledge in pedagogical contexts, such as textbooks.
It is important to note that contextualization in relation to sociolinguistics only examines how language is being used. This is because sociolinguistics is the study of how society uses language.