Introduction 1. Mutations in Standard Welsh 2. Previous Accounts of Mutation 3. Comparative and Historical Aspects of Mutation 4. The Phonetics of Mutation 5. The Phonology of Mutation 6. The Syntax of Mutation 7. Interfaces 8. The Semantics of Mutation 9. The Psycholinguistics of Mutation 10. The Sociolinguistics of Mutation 11. The Future of Mutations Notes Appendices References Index