Thus, two epistemological horizons are to be separated from one another; namely, the speaker’s knowledge and the linguist’s knowledge. Additionally, there is another differentiation that must be kept in mind with respect to the speaker’s knowledge: First, there is the segment of ‘procedural’ knowledge, or the ability to do something – in this case, the ability to speak. More specifically, this refers to the natural use of a variant, be it conventionalized or in some cases even new; it can also refer to spontaneous switching between varieties or languages. Second, there is the complementary segment of ‘declarative’ knowledge, which can be described for the purposes of variational linguistics as representations that are associated with the variants and their usage, such as ‘I understand this expression, but it is false’; or ‘this expression is only used by youth in the city, older people in the countryside or by migrant speakers with a particular ethnic background’, etc.1
Procedural knowledge is still situated strongly in the foreground of linguistics, because the relevant data consist primarily, and in many cases exclusively of utterances, i.e. speech production. Declarative knowledge, however, is crucial in describing variation: In a sense, variational linguistics and linguistics of varieties are at their cores nothing more than the elevation of procedural and declarative speaker knowledge to the epistemological level of the linguist.