On the old Irish third palatalisation and the 3sg. present of the copula

A few years ago, two articles (Breatnach 2005b, Griffith 2007) noted small exceptions to the Old Irish third palatalisation. Here, I re-examine these exceptions, add a few examples to the roster of forms showing them, offer a possible interpretation of the phonetic basis of the exceptions, and explore how this can help explain a puzzling form of the copula in Old Irish. Finally, in the appendix, I examine forms of the preposition etar ‘between’ and offer an explanation for their phonological development.