This thesis concerns the word formation of secondary verbs in Old Irish. Although extensive work has been done on primary verbs, the secondary adjectives and the nouns in Old Irish, and the formation of causatives and iteratives and that of the verbal nouns in Welsh, the secondary verbs in Old Irish have been almost entirely ignored (with the exception of the deverbal verbs in -igidir), while they provide fascinating insights into the process of word formation in Celtic and Early Irish. Their importance lies especially, but not exclusively, in the obvious productivity of this morphology in Old Irish and in the visible development of the morphology from Proto-Indo-European through Old Irish. The formation of secondary verbs in any language and indeed in any stage of that language shows the creativity of the users of that language and the secondary verbs in Old Irish show the creativity of the speakers of Old Irish and its antecedents.
The thesis consists of five chapters and two appendices. The first chapter contains the preliminaries, the theoretical, material and methodological basis of the thesis. The second chapter is an introduction into the Old Irish verbal system and its origins to set the stage for the remaining chapters. The third chapter is the analysis, morphological, semantic and statistical, drawn from the corpus. The fourth chapter is the conclusion. The fifth chapter contains all the secondary verbs found in the Würzburg and Milan glosses with cognates, discussion and notes. The first appendix contains those primary verbs that have taken on weak flexion and the second all the other primary verbs, for comparative purposes.