Reassessing inflectional regularity in Modern Greek conjugation
Authors: Stavros Bompolas, Marcello Ferro, Claudia Marzi, Franco Alberto Cardillo, Vito Pirrelli (University of Patras, CNR-ILC, 2016)
Topic: Lexical and Semantic Resources and Analysis

Abstract
Paradigm-based approaches to word processing/learning assume that word forms are not acquired in isolation, but through associative relations linking members of the same word family (e.g. a paradigm, or a set of forms filling the same paradigm cell). Principles of correlative learning offer a set of dynamic equations that are key to modelling this complex dynamic at a considerable level of detail. We use these dynamic equations to simulate acquisition of Modern Greek conjugation, and we compare the results with evidence from German and Italian. Simulations show that different Greek verb classes are processed and acquired differentially, depending on their degrees of formal transparency and predictability. We relate these results to psycholinguistic evidence on Modern Greek word processing, and interpret our findings as supporting a view of the mental lexicon as an emergent integrative system.

Introduction
Issues of morphological (ir)regularity have traditionally been investigated through the prism of morphological competence, with particular emphasis on aspects of the internal structure of complex words (AUTHOR). Within this framework, one of the most influential theoretical positions is that morphologically, phonologically, or/and semantically transparent words are always processed on-line through their constituent elements, whereas irregular, idiosyncratic (non-transparent) forms are stored (and retrieved) as wholes in the lexicon (Pinker and Prince, 1994). Likewise, AUTHOR assume that the past tense formation of regular verbs in English requires on-line application of an affixation rule (e.g. walk > walk+ed), while irregular past tense forms, involving stem allomorphy (e.g. drink > drank), are retrieved from the lexicon. Modern Greek introduces an interesting variation in this picture. First, stem allomorphy and suffixation are not necessarily mutually exclusive processes, but coexist in the same inflected forms (e.g. lin-o ‘I untie’ > e-li-s-a ‘I untied’, aɣap(a)-o ‘I love’ > aɣapi-s-a ‘I loved’). Secondly, affixation rules may select unpredictable stem allomorphs: aɣap(a)-o ‘I love’ > aɣapi-s-a ‘I loved’, for(a)-o ‘I wear’ > fore-s-a ‘I wore’, xal(a)-o ‘I demolish’ > xala-s-a ‘I demolished’. These cases suggest that inflectional (ir)regularity is not an all-or-nothing notion in Greek. Different inflectional processes may compound in the same words to provide a challenging word processing scenario AUTHOR. From this perspective, Modern Greek offers the opportunity to test traditional hypotheses of grammar and lexicon interaction in word processing and learning, to explore the potential of single, distributed mechanisms in addressing word processing challenges AUTHOR.

Conclusion
Data analysis highlighted a hierarchy of regularity-by-transparency effects that appear to have consequences on morphological processing. In particular, the evidence offered here emphasises the role of formal preservation of the stem (or stem transparency) in the paradigm as a key facilitation factor for morphological processing. Our case study is focused on a distinguishing characteristic of Greek conjugation: all verb paradigms, both regulars and irregulars, involve (unpredictable) stem allomorphy in past-tense formation. Hence, the difference between regular and irregular verbs could not be attributed to the presence or absence of stem allomorphy as is the case with other languages, such as English and Italian (and, to a lesser extent, German), but rather to the type of stem allomorphy itself. The ﬁnding (Figure 2) that stem-ﬁnal systematic change, as in the case of regulars, led to signiﬁcantly easier recall than stem-internal vowel changes and non-systematic/non-predictable stem-final change, as is the case of irregulars, lends support to the conclusion that the type of stem allomorphy is what determines the different levels of morphological regularity in Greek. Crucially, this seems to involve a regularity-by-transparency interaction, with predictability playing second fiddle. Our data meet growing psycholinguistic evidence pointing in the same direction, to emphasise the importance of formal redundancy for speakers’ perception of morphological structure. Furthermore, it paves the way to the definition of a performance-oriented notion of inflectional regularity that may ultimately cut across traditional competence-based classifications, which presuppose a hardly tenable subdivision of work between storage and processing.