The representation of vocalic features in vowel alternations : Phonological, morphological and computational aspects

Abstract

A pertinacious issue within linguistics is the asymmetry of sound-meaning and meaning-sound relations. One sequence of speech sounds may convey more than one meaning, and vice versa, one meaning can be expressed by more than one speech sound sequence. This dissertation is concerned with a morphophonological asymmetry between underlying representations and surface forms. A case here are morphophonological vowel alternations, i.e. differing realisations of one vocalic phoneme dependent on the morphosyntactic context in which the corresponding word occurs. For instance, the vowel in the German noun Vater (father) either surfaces as back (dorsal) vowel [a] or as front (coronal) vowel [e], dependent of whether the noun is used in the singular or in the plural. A similar diachronic asymmetry, based on vowel height, can be found by comparing New Zealand English (NZE) and American English (AE). The English noun bat is realised with a mid vowel in NZE, while it has a low vowel in AE.The following questions arise:-How are vowel alternations and vowel shifts represented in the mental lexicon?-How do speaker and listener deal with the asymmetries between underlying and surface forms? In particular, how are alternating or shifted forms perceived and produced?This thesis provides theoretical and experimental evidence for a featurally underspecified representation of vowels in morphophonological stem alternations in German and for a particular vowel inventory in NZE which emerged as a consequence of language change, describable as a restructuring of contrastive features. The main tenets are that-the lexical representations themselves determine whether grammatical vowel alternations are possible and-the lexical representations account for possible diachronic language changes.The proposed model of speech perception and lexical access therefore covers both phonological and morphological aspects of lexical organisation and favours a single route access to all (i.e. complex and simplex) word forms. This access is based on the matching or mismatching of features extracted from a particular speech signal and features of word forms stored in the mental lexicon.The dissertation comprises five chapters. The first chapter describes the grammatical vowel alternations in German and introduces the model which tries to account for both the synchronic and the diachronic linguistic data. The second chapter reviews the psycholinguistic literature on speech comprehension. The third chapter includes a series of behavioural experiments, seeking support for the model introduced in chapter 1 while the fourth chapter adds neurolinguistic evidence for underspecified vowels in particular German nouns. The fifth chapter concentrates on a vowel change in another Germanic language, namely, in New Zealand English, and provides experimental evidence for a restructured vowel inventory.