In this response to Ellis's target article on frequency in language processing, language use, and language acquisition, we argue in favor of a role for frequency in several areas of second language acquisition, including interactional input and output and speech processing. We also discuss areas where second language acquisition appears to proceed along its own route and at its own pace regardless of the frequency of the input, as well as areas where input is infrequent but acquisition appears to be unimpeded. Our response is intended to highlight the complexity of the task of deciphering the role and importance of frequency.