Morpho-phonology is not independent of semantics

Abstract Morpho-phonological alternations in inflectional paradigms are commonly analyzed as purely formal phenomena, in which the mapping of phonological structure and morpho-syntactic categories is organized without recourse to semantic properties of the words involved. The present paper explores the role of semantics using the Discriminative Lexicon approach ( Baayen, et al. 2019 ). The test case explored in this paper is German nominal number, a system involving complex morpho-phonological variation (e.g. Köpcke et al., 2021 ; Heitmeier et al., 2021 ; Plag et al., 2024 ; McCurdy, 2024 ). Using word2vec vectors as semantic representations, and triphones as form representations, we created two-layer linear discriminative learning (LDL) networks that map form representations directly onto semantic representations (modeling comprehension), and semantic representations onto form representations (modeling production). The LDL mappings successfully predict the forms and the meanings of the singular and plural nouns taken from a pertinent study ( Domahs et al., 2017 ). A number of semantic and phonological measures derived from the LDL network also very successfully distinguished between singular and plural forms. Our results demonstrate that semantics, in addition to formal and grammatical properties, may play a decisive role in the representation and processing of German nominal number. The system of German nominal number can be understood as emerging from the distributional properties of words on the one hand, and basic principles of discriminative human learning on the other.