Indexicality is the process through which language is used to construct social identities. We can construct social identities using language (along with other social semiotic systems) because certain linguistic forms come to be ideologically associated with specific types of people. For example, H-dropping is stereotypically associated with the speech of working-class men. The social meaning attached to any linguistic form is not fixed and therefore specific social meanings are only activated in the context of use. The process of indexicality allows speakers to use language to directly index “stance, acts and activities” (Ochs 1992:335) which are ideologically associated with specific groups of people, and therefore the linguistic feature comes to indirectly index these associated social identities. For example, because H-dropping is associated with working-class men, in specific contexts a speaker may be able to use this variable in order to index a specific type of masculine personae, one which is, for instance, based on physical rather than structural power.
Ochs, Elinor.1992. Indexing Gender. In Alessandro Duranti and Charles Goodwin. (eds.) Rethinking Context: Language as an Interactive Phenomenon, 336-359. Cambridge: Cambridge University Press.