This book examines various aspects of Celtic linguistics from a general and more specific point of view. Amongst the topics investigated is the system of Irish initial mutations from both a linguistic universal and contrastive perspective. Other contributions analyse and cast new light on deverbal adjectives and assertive and declarative speech acts in Irish, communication and language transmission, change and policy, Breton and Sorbian grammars, as well as other issues of sociolinguistics in Irish, Welsh and Breton.