quote: Á = do + a.
Er, no. Á= ag+a.
Normally you have "ag díol" ("at selling"). Ag díol na dtithe (selling the houses, "at selling of the houses").
But with the pronoun object of the verbal noun, ag+a becomes á. Note this construction ca also be analogous to passive in use.
Táim á dhíol (I am selling it, a masculine pronoun object)
Tá sé á dhíol agam (it is being sold by me)
Táim á díol (I am selling it, a feminine pronoun object)
Tá sí á díol agam (it is being sold by me)
Táim á ndíol (I am selling them, a plural pronoun object)
Táid siad á ndíol agam (they are being sold by me)
Other pronoun objects:
Tá sé am dhíol - he is selling me
Tá sé ad dhíol - he is selling thee
Tá sé ár ndíol - he is selling us
Tá sé úr ndíol - he is selling you
These all derive from ag+the pronoun concerned.
The forms above are the Cork forms.
Let's look at Cois Fhairrge (Galway), from Ó Siadhial's Learning Irish:
go mo dhíol - selling me
go do dhíol - selling thee
ghá dhíol - selling him
ghá díol - selling her
ghá ndíol - selling us
ghá ndíol - selling you
ghá ndíol - selling them
Note Ó Siadhial's spelling are "do mo", "do do", "dhá", "dhá", "dhá", "dho'ur" and dhá", but the pronuunciations are as I have given them - he seems to refuse to believe the evidence of his own eyes that the pronoun object derives from "ag".
The pronunciations "go mo" and "go do" are derived etymologically from "ag". Ghá them emerges by lenition of the "g".
[Note: I don't know what the Donegal forms are. But Lars Braesicke gives them as "(ag) mo dhíol, (ag) do dhíol, á dhíol, á díol, (ag) ár ndíol, (ag) bhur ndíol, á ndíol" - I am a bit confused by these, as I thought "bhur" was "mur" in Donegal - I am seeking confirmation on the Donegal forms.]
I see in Gaeilge Chorca Dhuibhne the Kerry forms are as for Cork, but the third person á dhíol can also be dhá dhíol and dá dhíol - these also derive from "ag". Ag a-->gá-->ghá (same pronunciation as dhá)-->dá (by delenition from dhá/ghá). As the gh could come from a g or a d, the ghá is non-etymologically delenited to dá sometimes. This was railed against in the 19th century by the great linguist John Donovan in his 1845 grammar, John Donovan being the "mothership" in terms of Irish grammar. Ulick Bourcke in 1856 also raised against dá, saying it was newfangled thing in his day, and an incorrect etymology.
The CO forms are "do mo dhíol, do do dhíol, á dhíol, á díol, dár ndíol, do bhur ndíol, á ndíol" - these forms don't seem to be right anywhere (I am told "the CO was devised by experts with a detailed knowledge of the most common dialectal forms, which they adopted"???), although they do have the advantage of disobliging speakers of all dialects. More importantly, the devisers of the CO seemed to think (incorrectly) that there was etymologically a "do" there...