I'm working on transcribing some of the stores Mac Coisdealbha took down from Éamonn a' Búrc, mainly because he writes in such a dialectal manner that it's one of the best resources for getting Connemara Irish pronunciation (including sandhi effects, at times!), and I've see the phrase 'agá n-a' used a few times now. I realize it's 'ag a' (agá n-athair, with the a elided and agá n-a dhreithiúr), but was wondering if anyone knew the etymology for it, or how I could describe it? I make notes of interesting dialectal features on the blog I transcribe these on, and definitely want to include this.

Also, does anyone know if it's still productive in Connemara?

It is just an infixed syllable -án-:
agána, arána, chuigeána, etc. for ag a, ar a, chuig a
See The Irish of Iorras_Aithneach https://www.dias.ie/wp-content/uploads/ ... lume_3.pdf
9.167 (p. 1829):
"Infixed or linking [...] -án- is obsolescent."

Thanks Labhars. Was unable to find it in IIA myself.