In this chapter I introduce the learning and processing model CASP (Complex Adaptive System Principles) for Bilingualism, which can be used to capture the overall linguistic behaviour of different types of bilinguals. One of the advantages of the proposed model is that it is not limited to any one theoretical framework but is relevant for, and applicable to, many different theoretical approaches. Numerous speaker-specific (internal) and situation-specific (external) factors that we discussed in the previous chapter will be shown to affect the ways in which the proposed general principles interact and affect the outcome predicted in the model. The proposed model will make it possible for us to make predictions that take into account multiple factors. Namely, I will show that the same processing principles operate in all situations, but the manner of their competition or collaboration is driven by the internal and external factors that I referred to, which is what ultimately conditions different outcomes.