How does the bilingual brain distinguish and control which language to use? A large body of research has been dedicated to answering this question by mainly using the language switching paradigm that taps into different language control mechanisms. This research has been fruitful in revealing both the time course and the brain areas involved in bilingual language control. In this chapter, we review this research and derive two main conclusions. First, the cognitive and neural mechanisms involved in bilingual language control seem to be influenced by various sociolinguistic factors, including language proficiency. Second, “sustained” and “transient” components of control are differently involved in the control of the two languages because they recruit different brain networks. This observation may suggest that different qualitative processes are applied to dominant and nondominant languages to ensure successful speech production in bilinguals.