Establishing contact: Slavonic influence on Romanian morphology?

It is not disputed that Slavonic languages have influenced the inflexional morphology of Romanian and its closely related Daco-Romance varieties. For example, Romanian vocatives in -o, Istro-Romanian perfective verb-roots, and probably the Megleno-Romanian first and second person singular endings -um and -iʃ, are all attributable to Slavonic. These cases generally involve loans of ‘morpheme’-like entities, phonological strings associated with a particular grammatical meaning. However, it has recently been suggested (e.g., by Elson, 2017) that certain Romanian paradigmatic patterns of root allomorphy in the verb, notably those involving the effects of palatalization, are influenced by Slavonic models. Some of these patterns appear to be of a qualitatively different kind from run-of-the-mill ‘morphemic’ loans, in that they are autonomously morphological, and cannot be associated within any coherent grammatical meaning. The borrowing of such purely morphological patterns under conditions of language contact has not hitherto been attested in the literature on language contact, and the evidence for such cases in Romanian deserves careful scrutiny. Unfortunately, the arguments provided for these putative borrowings can be shown to be rest on seriously flawed assumptions. Examination of those arguments serves to focus our attention on the kind of criteria that need generally to be met if the effects of language contact in morphology (or any other domain) are to be plausibly demonstrated. In particular, I shall emphasize the need for appeals to language contact carefully to exploit the full range of available comparative evidence, and to establish rigorous criteria to exclude the possibility that apparent contact effects are explicable by factors internal to the history of the recipient language