Parameters constitute options provided by Universal Grammar (ug). These options are sometimes formulated in terms of binary choices having the value +/−. For example, does a particular grammar have verb raising or not? Does a particular grammar require overt subjects or not? These options can also be formulated in terms of the values a variable may take. For example, assuming the rule Move α to account for the movement of constituents, what are the values for α in a particular grammar? These options may also be formulated in terms of correlations, for example, property (b) will be available in a given grammar if property (a) is. As we will see throughout this chapter, parameters account for the relationship between a number of properties which, at first glance, would appear to be unrelated.

In the theory advocated in this book, it is hypothesised that, in creole genesis, the creators of a creole do not have sufficient access to the superstratum language to acquire its parametric values. By hypothesis, the creators of the creole use the parametric values of their own grammar in assigning a value to the parameters of the language that they are creating. This hypothesis predicts that, where the parametric values of the substratum and superstratum differ, the creole should have the same value as the substratum languages. With one exception, this prediction is borne out in Haitian creole, as we will see below. The following parameters will be discussed: availability of null subjects, verb raising, the serial verb construction and the double-object construction, interpretation of negative quantifiers and availability of verb-doubling phenomena.