Modularity and stratification in phonology: Evidence from Scottish Gaelic

  • Donald Morrison

Student thesis: Phd


This thesis presents evidence from Scottish Gaelic for modularity and stratification in phonology. Modularity refers to the separation of the linguistic grammar into several components that each deal exclusively with a particular level of linguistic structure, such as morphosyntax, phonology and phonetics, and which communicate with one another in a tightly constrained manner. Strict versions of modularity face a challenge from widespread reports of direct lexical or morphological conditioning of gradient phonetic detail, which cannot be accounted for under the common assumption that the phonetics is sensitive only to the categorical output of the phonology. Stratification refers to the existence of different sets of phonological rules applying to different morphosyntactic domains, such as stems, words and entire utterances, which can account for opacity in morphologically derived forms. Specifically, I argue in favour of Stratal Optimality Theory, which is a stratified version of traditional Optimality Theory. The thesis consists of four research papers which approach these theoretical questions from various angles. The first paper reports an acoustic study that explores the distinction between phonetic and phonological sound patterns by investigating interspeaker variation in a number of allophonic oppositions in the vowel system of the dialect of Scottish Gaelic spoken in Ness, Lewis, some of which have never been reported before in the existing literature. It is found that these oppositions are categorical and phonological for some speakers, but gradient and phonetic for others. The second paper reports a nasal airflow study in which both gradient phonetic and categorical phonological patterns of vowel nasalisation are found to occur in Scottish Gaelic. In accordance with the predictions of a strictly modular architecture, only phonological nasalisation is found to be sensitive to morphological conditioning, while phonetic nasalisation always applies transparently. The third paper presents a detailed metrical analysis of the prosodic contrast between Class 1 and Class 2 forms in Scottish Gaelic, which are distinguished on the surface by either tonal accent, glottalisation or overlength depending on dialect. It is shown that Stratal Optimality Theory is capable of accounting for the complex patterns observed, including numerous opaque interactions between segmental and prosodic structure, in a principled manner. Finally, the fourth paper presents a detailed analysis of the opposition between broad and slender vowels and consonants in Scottish Gaelic, showing that the broad or slender quality of a vowel is almost always derived phonologically from that of the adjacent consonants. Stratal Optimality Theory is shown to be capable of accounting for highly complex opaque interactions between the broad-slender opposition and various morphological processes. These four papers together show that the Scottish Gaelic data are particularly amenable to analysis within a framework in which the grammar is modular and phonology is stratified. This thesis therefore demonstrates the degree to which the complex sound system of Scottish Gaelic can inform linguistic theory. It also provides vital documentation of an endangered language, and offers unprecedentedly thorough treatments of several aspects of Scottish Gaelic phonology.
Date of Award31 Dec 2020
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorRicardo Bermúdez-Otero (Supervisor) & Wendell Kimper (Supervisor)


  • paradigm uniformity
  • Scottish Gaelic
  • Stratal Optimality Theory
  • tonal accent
  • svarabhakti
  • overlength
  • stratification
  • Optimality Theory
  • palatalisation
  • nasal airflow
  • modularity
  • metrical structure
  • initial mutation
  • incomplete neutralisation
  • glottalisation
  • copy epenthesis
  • absolute neutralisation
  • nasalisation

Cite this