Overabundance in Italian verb morphology and its interactions with other non-canonical phenomena

The paper deals with overabundance, i.e., the situation in which a cell in a paradigm is filled by two synonymous forms which realize the same set of morphosyntactic properties (as in Italian devo and debbo 'must.1SG.PRS.IND'). Such forms are called cell-mates. A number of instances of overabundance in Italian verb paradigms are described, and conditions on the appearance of each form in a set of cell-mates are discussed. It is shown that certain sets of cell-mates are less canonical, in that one of the two forms is only found in diachronically, diatopically, diaphasically or diastratically conditioned contexts, while other sets show no such conditioning, and are therefore canonical cell-mates. The second part of the paper explores interactions between overabundance and other non-canonical morphological phenomena such as suppletion, syncretism, periphrasis, overdifferentiation, and morphomic partition classes.