Can somebody please help with a pronunciation question?

"Is déirce dá chuid féin don amadán." This proverb struck my funny bone, but listening to its sound file causes questions for me.

dá is pronounced as "ah"... or so I heard it. Is this regional or can one correctly say "dah"?

Also, "don" is pronounced as "gon". I've run into this before. Are there any hard and fast rules as to when D or DH are pronounced as G or GH?

Thank you!

(I apologize in advance if this posts multiple times; for some reason the site keeps returning an error message telling me I must "revise" my post.)

That's iinteresting about the d>g change. Is that dialect specific or across the board?

/ɡənˠ/ ('gan') may be (one of) the Connacht form(s) of 'don' as 'do' can be pronounced as 'ga'

'ag dul' is as 'a gol', which may have an historical reason for its form

'd' would mostly be a d

dh and gh are usually the same sound

Dennis might knoe about the history of this and other examples

Actually dul is goil in Connacht. It's a sort of mixed word made up of dul and gabháil (in Cois Fhairrge dialect gabhfaidh = rachaidh).
Do and de both became 'go' in Conamara probably because the forms like dom, duit..., díom, díot... are almost always lenited in these dialects: dhom, dhíom... which can also be understood as ghom, ghíom... (since gh and dh are pronounced in the same way). The influence of the preposition 'go' is also included.
Slán
Daithí