Peter McQuillan analyzes a number of key words in the Irish language--duchas, duthaigh, dual, and saoirse--along with derivatives and associated terms in order to reveal their relationships to historical and cultural texts. He demonstrates how the pragmatic, semantic, and syntactic range of these terms evolved over time in relation to differing historical conditions, thereby underscoring characteristic features of the Irish language and of Irish cultural attitudes, practices, and experiences. McQuillan establishes affiliations between these ranges and the sometimes catastrophic changes that beset the culture in which these concepts played such a defining role. The discussions are situated within the linguistic-anthropological theories of Boas, Sapir, Whorf, Voloshonov, Pierce, Saussure, and other scholars, such as Silverstein and Wierzbecka.