this book is obviously the standard, but it is very very philological and an awful lot of the conjugations are being provided for the purposes of taxonomising endings rather than what I presume anyone reading this book outside of an academic context would be doing, which is trying to read sagas in the original, or deepening their understanding of the ancestry of the language as spoken. I can't imagine anyone would ever have a use for the dual prepositional case of the word 'ounce' or the vocative of 'prayer' for example.
all to say that even with decent Irish and some knowledge of the grammar I found it very hard going. presume people who can read that pronunciation notation would have an easier time. fascinating to see those many instances in which old Irish writing reads more like the way native speakers (of Gaeilge 'nua') today use it, e.g. 'calideb' for sword, 'dénum' for doing