In Munster Irish, when Dom is suffixed with an emphatic pronoun i.e. domsa, it can be pronouned as /do:sə/.
Otherwise its just pronouned as dom.
I dont know why they do that either Lughaidh, its probably because they learned the CO, but know some dialectal traits, so they stick them in every now and again.
_________________
Is Fearr súil romhainn ná ḋá ṡúil inár ndiaiḋ
(Amhlaoibh Ó Súilleabháin)
Please wait for corrections/ more input from other forum members before acting on advice
I'm familiar with Munster Irish/ Gaolainn na Mumhan (GM) and the Official Standard/an Caighdeán Oifigiúil (CO)