The diachronic link
A major purpose of this work is to illustrate the need for any explanation of linguistic regularity to address the problem of what causal mechanisms (phylogenetic or ontogenetic) could have been responsible for the incorporation of the regularity into actual language systems. This is required not only as an evaluative measure, i.e. to show that the explanans could viably lead to the explanandum (cf. Clark and Malt 1984; Bybee 1988), but also because it can be of vital importance in the strict characterisation of the explanandum and in the development of a precise and thorough explanans. In the first part of this chapter (4.1), I examine a potential diachronic 'explanation' for the suffixing preferen~e documented in chapter 2. The explanation is derivable from work by Giv6n (1971b), and leads Cutler et al. (1985) to reject diachronic principles in their psycholinguistic account since such factors arise in what they perceive as part of a 'competing' explanatory model. I call into question the explanatory potential of the historical account, but accept Giv6n's assumptions about the diachronic affixation process (introduced in chapter 3); I then proceed (4.2) to show how the semantic and phonological processes involved are crucially relevant to our structural regularity and its explanation. In addition, I make the claim that certain semantic and phonological descriptive principles assumed in the literature to be primitive notions, are, in fact, transparently derivable from higher level phenomena.