This contribution addresses a number of conceptual and methodological issues regarding processes of dialect change leading to koineization. After a discussion of some notions and key findings from a few recent relevant studies concerning present-day Dutch dialects, two paradigms of linguistic theorizing will be briefly presented. Next, these paradigms will be compared on the basis of the findings from a recent diachronic study of the deletion of postvocalic /r/ before coronal obstruents. It will be shown that only one of the paradigms survives this test. As to the internal factors, the study offers evidence for the claim that, as far as phonological and morphophonological variation is concerned, the place of a given dialect feature in the typology of phonological rules plays a determining role in its chances for survival in situations of long-lasting, extensive dialect contact. Finally, attention will be paid to some desiderata and possibilities for further research which are either of a methodological (especially data related) or of a more theoretical nature.