Few people would dispute that speaking more than one language poses additional challenges above and beyond those faced if there is only one language to contend with. The necessity for bilinguals to keep separate and to coordinate their lan- guages raises an important question that has been central to much of the work on bilingual processing, namely whether becoming a bilingual entails only quantita- tive changes in one’s language production infrastructure (e.g., additional lexical entries, a larger phoneme inventory) or whether it brings about more qualitative changes (e.g., a system dedicated to language control). In this chapter we will delve deeper into purported processing differences between monolinguals and bilinguals and attempt to ascertain whether they constitute qualitative and/or quantitative changes in the language production system. To this end, we shall take current knowledge of monolingual language production as our starting point and will attempt to uncover potential differences between monolinguals and bilin- guals at each level of processing.