> <<Derb Fhorgaill ingen ríg Lochlainne ro charastar Coin
> Culaind ara urscelaib.>>
> Derb Fhorgaill was the daughter of the king of Lochlann
> who loved Cuchulainn because of his famous stories.
> I assume "Derb Fhorgaill" is a woman's name, maybe translates
> something like "certain witness";
Actually, "Daughter (der, derb) of Forgoll". "Der" is limited
pretty much to personal names and poetic usage.
> it seems strange to see a name in the front of
> the sentence where I'd ordinarily expect a verb. Maybe the
> copula is understood, like in modern Irish.
I think that's it, fronting for emphasis: "It was Derbfhorgaill,
the daughter of the king of Norway, who loved...."
> "urscelaibh" is equivalent to "airscel" which DIL translates
> as "airscél, famous tale."
Your translation above is exact. What it implies, I think, is
something like "... who loved CC on account of (having heard)
tales of his exploits."
> <<Dolluid aniar i rricht dá géise
> 7 a hinailt co mbátar for Loch Cuan 7 rond óir eturru.>>
> She and her maidservant came from the west in the form of
> two swans until they were above Loch Cuan with a golden chain
> between them.
Ooops. I'm responsible for a genuine typo here. The text has
"anair" (= from the east), not "aniar" (= from the west). Sorry!
I took "for" (the forerunner of modern "ar") to mean "on, upon"
rather than "above" in this context; that is, the two swans were
swimming on the lake at that point rather than flying above it.
But I guess either interpretation is possible.
> <<Amal ro boí dano Cu Chulaind 7 Lugaid a dalta .i. mac
>> na Tri Find Emna laa and la toíb ind locha co n-accatar
>> na heonu.>>
> Likewise Cuchulainn and Lugaid his foster child, who was son
> of the three Fionns of Emna were also there one day by the side
> of the lake so that they saw the birds.
The use of "ama(i)l" here is worth considering. According to
similar examples in DIL (s.v. "amail", II.c) we should translate
this as "while, when, as": "While CC and L ... were beside the
lake one day they saw...."
But I can't help also comparing the syntax of Modern Irish "is
amhlaidh a bhí CC agus Lughaidh..." (= it is the way that CC and
L were... = it so happened that CC and L were...), which uses a
related reflex of "(s)amail".
Go raibh míle maith agat as ucht an aistriúcháin, Liz!