Speakers extrapolate community-level knowledge from individual linguistic encounters

Speakers' lexical choices are affected by interpersonal-level influences, like a tendency to reuse an interlocutor's words. Here, we examined how those choices are additionally affected by community-level factors, like whether the interlocutor is from their own or another speech community (in-community vs. out-community partner), and how such interpersonal experiences contribute to the acquisition of community-level linguistic knowledge. Our three experiments tested (i) how speakers' lexical choices varied depending on their partner's choices and speech community, and (ii) how speakers' extrapolation of these choices to a subsequent partner was influenced by their partners' speech communities. In Experiment 1, Spanish participants played two sessions of an online picture-matching-and-naming task, encountering the same pictures but different confederates in each session. The first confederate was either an in-community partner (Spanish) or an out-community partner (Latin American); the second confederate was either from the same community as the first confederate or not. Participants' referential choices in Session 1 were influenced by their partner's choices, but not by their community. However, participants' likelihood to subsequently maintain these choices was affected by their partners' communities. Experiment 2 replicated this pattern in Mexicans, and Experiment 3 confirmed that these results were driven by confederates' communities, rather than perceived linguistic status. Our results suggest that speakers encode speech community information during dialogue and store it to inform future contexts of language use, even when it has not affected their choices during that particular encounter. Thus, speakers learn community-level knowledge by extrapolating linguistic information from interpersonal-level experiences.