The diphthongs əi and a1 in Scottish, Scotch-Irish and Canadian English

The Development of generative phonology to deal with the phonological component of transformational grammars has in recent years led to many fruitful insights in the analysis and description of synchronic states of languages. It was inevitable, however, that generativists should eventually turn their attention to historical linguistics and seek to re-interpret the olderlawsof sound change in terms of modernrules, recognizing specifically the effects of the addition of new rules, the extension of rules by the removal of constraints, and the deletion or re-ordering of rules (King 1969: 39-63).