There is no doubt that cognitive control and language processing are intertwined: Prefrontal cortical regions that support the ability to resolve competition between multiple, incompatible representations are recruited for both language production and language comprehension. In this talk, I will explore a somewhat less intuitive hypothesis, namely that cognitive control has both benefits and costs for language processing. After introducing the motivation for this hypothesis, I will provide evidence from three experiments in which we manipulated frontally-mediated cognitive control processes using noninvasive brain stimulation (transcranial direct current stimulation; TDCS) and observed the consequences for different aspects of language processing. I will present results from one experiment that shows a benefit of cognitive control (a categorization task), a second that shows a cost of cognitive control (a different categorization task), and a third that shows both costs and benefits (a word production task).