This registered report article investigates the role of language as a dimension of social categorization. Our critical aim was to investigate whether categorization based on language occurs even when the languages coexist within the same sociolinguistic context, as is the case in bilingual communities. Bilingual individuals of two bilingual communities, the Basque Country (Spain) and Veneto (Italy), were tested using the memory confusion paradigm in a 'Who said what?' task. In the encoding part of the task, participants were presented with different faces together with auditory sentences. Two different languages of the sentences were presented in each study, with half of the faces always associated with one language and the other half with the other language. Spanish and Basque languages were used in Study 1, and Italian and Venetian dialect in Study 2. In the test phase, the auditory sentences were presented again and participants were required to decide which face uttered each sentence. As expected, participants error rates were high. Critically, participants were more likely to confuse faces from the same language category than from the other (different) language category. The results indicate that bilinguals categorize individuals belonging to the same sociolinguistic community based on the language these individuals speak, suggesting that social categorization based on language is an automatic process.