DCT implies that language emerged when a protoverbal code of some kind attached itself to an established (although still evolving) nonverbal cognitive system. The most recent evolutionary phase involved increasing functional autonomy of the verbal system, in keeping with the DCT assumption that evolved nonverbal and verbal cognitive systems are functionally independent but interconnected, so that one or other or both systems can be used in memory and other tasks. Normal language behavior entails a continual interplay between the two systems. However, the theory further implies that, initially, language development was completely dependent on the nonverbal cognitive base and gradually became capable of functioning independently for some purposes. The hypothesis is the main theme of this chapter and the subsequent one on syntax.