A chairde,
again, I had time to work on the novel and as a result here are a few more questions... Thank you all a lot in advance!
A Aonghuis, for a grammar freak (that I am) it was (and still is) ambaressing to make such a mistake – GO raibh maith agat as ucht do chabhair. One can only learn from mistakes :-)

1) what’s “ciacu”? at first, I thought it was a form of “chuig” but that doesn’t seem to be right...
2) p. 8: am I right that “sarar” is another version of “sular”?
3) “is mór go léir”=?
4) the exact meaning of the blessing: “Go neartaí Dia a lámh atá ag obair do shíor ag nochtadh seanaimsireacht na cruinne.” (furthermore, I couldn’t find ‘seanaimsireacht’...)
5) “tráth” in: “Bhíodh an caighdeán ag déanamh tinnis do Sheoirse tráth...”
6) I guess this is a proverb: “Cloch eile ar charn Sheoirse ...”
7) p. 11: the first sentence “Níl bhaol ná gur breá í an óige, cé go bhfuil sí fá réim agamsa fós, agus ní thagann ciall roim aois.” is a bit difficult. I think I know what he wants to say, that childhood is not as half as fine although he had already ??? and sense doesn’t come before age. Or is “roim aois”=before my age?
8) “ó cheann ceann na bliana”
9) “méiscreach” = ?
10) couldn’t find “fé choimhde”
11) is “dá dheascaibh sin” another form of “de dheasca”=as a result of?
12) “gleoch” comes from “gleo”, right? so, does it mean sth. like ‘noisy’?
13) “ní galar éinne amháin é”
14) what’s the meaning of “stranfhiacal”?

Well, that should do for now (one page at a time...)
Le meas,
Stefan

1) ciacu I think this is "cé acu" which of
2) Yes
3) Out of context, I'd guess "there are very many"
4) Go neartaí Dia a lámh may God strengthen his hand
"atá ag obair do shíor ag nochtadh seanaimsireacht na cruinne" who is always laboured to expose the ancientness of creation.
5) At one time
6) Yes. The old custom before a battle was for the warriors to place a stone on a heap of stones before the battle. After the battle, the survivors tokk away a stone. The remaining pile showed how many didn't survive. The proverb means to add something to the memorial of a person, i.e. to praise them, or to admire something they have done.
7) "Níl bhaol ná" "There is no doubt that"
"gur breá í an óige" youth is a fine thing
"cé go bhfuil sí fá réim agamsa fós" although I am still young
"agus ní thagann ciall roim aois." Reason does not come without age
8) From one end of the year to the other, i. all year
9) Drunk? Not sure w/out context.
10) At a guess "in the company of"
11) yes
12) yes
13) It is not something only one person suffers from
14) Dunno!

I second the answers above. The meaning of stranfhiacal is a prominent tooth.

Recte:
atá ag obair do shíor ag nochtadh seanaimsireacht na cruinne" who is always labouring to expose the ancientness of creation

well, i believe it won't seem meaningless if i keep thanking you over and over again but i hope you know how much i appriciate your help!

the context of 3) is "is mór go léir an cion agus an grá a bhí acu orm..." so your guess seems to fit.

9) "... go bhfuil síonta na spéire ... ag síorstealladh gan staonadh ... i gcoinne na gcarraigeacha méiscreach ..." maybe sth. like huge...

14) well it's all about dialect, isn't it? standard starrfhiacail -> stranfhiacail
no wonder i couldn't find it :-)

I was wrong on 9 so. I'll have a look at Dinneen later. I don't think it's huge, I'd say it is something like jagged or rugged.

méi(r)screach - craggy, rough is what is meant.
Dineen gives méiscre as an alternative spelling of méirscre