People learn language from their social environment. Therefore, individual differences in the input that their social environment provides could influence their linguistic performance. Nevertheless, investigation of the role of individual differences in input on performance has been mostly restricted to first and second language acquisition. In this paper I argue that individual differences in input can influence linguistic performance even in adult native speakers. Specifically, differences in input can affect performance by influencing people’s knowledgebase, by modulating their processing manner, and by shaping expectations. Therefore, studying the role that individual differences in input play can improve our understanding of how language is learned, processed and represented.