Natural and ad hoc hierarchies in Hungarian morphophonology

In Hungarian morphology, suffixed word forms display vowel/zero alternation. The distribution of the unstable vowels at the root–suffix morpheme boundary, commonly referred to as linking vowels, appears to be conditioned by a multitude of factors including several interacting aspects of the phonology of the word and its morphology (Siptár & Törkenczy 2000); in fact, the conditions of the occurrence of linking vowels are unpredictable, i.e. lexically determined. Beyond the basic dilemma of binary occurrence versus non-occurrence, linking vowels also exhibit occasional overabundance, i.e. cases where both possible forms are accepted realizations of the same paradigm cell (Kálmán et al., 2012). The loci of such overabundance are not trivial to predict either. Rebrus (to appear) observes that mapping out word paradigms in a suitably ordered two-dimensional table of roots and suffixes reveals the distribution of linking vowels to be less haphazard than it might seem at first: two strikingly separate areas of certainty emerge in the table, one with linking vowels and the other without linking vowels, although with a not-so-neat staircase-like border between them. Along the border we find some overabundant cells. He suggests that such a pattern may be the result of a gradual erosion of an earlier cleaner, more distinct and unambiguous separation of the two areas over the history of the language – a process of erosion driven by analogical attraction between neighboring forms. We propose a rough computational model to simulate what such a gradual transformation driven by analogy might unfold like over time, and use it to evaluate the hypotheses that local analogical pressures will 1) almost always dismantle an initial rectangular division of the two rival areas; and 2) usually keep the convex, “monotonic” shape of the division intact. We find support for these assumptions under reasonable free parameter settings. A tangentially related investigation into a subset of linking vowels’ distribution from a purely phonological viewpoint found the same staircase shaped separation, this time arising from a natural ordering of phonological forms (Blaskovics 2024), hinting that these kinds of patterns may be more widespread than initially assumed.