At 4:43:13 PM on Tuesday, July 9, 2013,
elliot.holland@... wrote:

> •Hann var maður héraðríkur og málamaður mikill.

> --He (nom) was (a) man (nom. modern spelling)
> district-powerful (powerful in his district mas. nom.
> compar.) and a great (no decl) lawyer (mála-fylgjumaðr).

If by ‘compar.’ you mean ‘comparative’, no: it’s just the
nom. sing. masc. of the positive (base) form of the
adjective. <Mikill> is also inflected: it’s the nom. sing.
masc. of the strong adjective declension.

> --He was a powerful man in his district and a great
> lawyer.

Looks good.

> •Þau Þorkell og Guðrún áttu son. Sá er nefndur Gellir.
> Hann var snemma hinn efnilegasti.

> --They (n. nom) Thorkell and Gudhrun had (a) son (acc.).
> That (loc. mas. nom.), he (conj. masc. nom.) was named
> (past part or adjectiveÞ) Gellir. He was quickly promising
> here/there/that? dem. pro. (masc nom or acc.

<Sá> is a demonstrative pronoun, 'he, that one (masc.)';
<er> is 3rd sing. pres. indic. of <vera>, and <nefndur> is
the nom. sing. masc. of the past participle.

<Snemma> can be either 'quickly, soon' or 'early'. Here I’m
inclined to go with the latter, though there really isn’t
much difference in sense in this case. <Efnilegasti> 'most
promising' is the nom. sing. masc. weak adjective inflection
of the superlative of <efnilegur>; <-ast-> is the
superlative suffix. The weak declension is required with
the determiner <hinn> 'the' (nom. sing. masc.). <Hinn
efnilegasti> is a noun phrase without the noun: 'the most
promising ...', where the ellipsis can reasonably be filled
in quite a few different ways without significantly
affecting the meaning.

> --They, Thorkell and Gudhrun had a son, who was named
> Gellir. He was quickly promising.

They, Þorkel and Guðrún, had a son. He was named Gellir.
[From] early [on] he was the most promising [of youngsters].

> •Þorleikur bróðir hans var að Helgafelli.

> --Thorleik (name? Nom.) brother (nom) of him was to on
> Helgafelli.

> --Thorleikur´s brother was at Helgafelli.

As you said, <Þorleikur> is nominative, not genitive, so it
can’t be 'Þorleik’s brother'; <bróðir hans> is an appositive
further describing Þorleik, 'Þorleik his brother' (where
'his' refers to Bolli Bollason, though this isn’t evident
without the preceding sentence of the full text). <Var> is
literally 'was', but in this context 'stayed' captures the
intended sense better. (This usage occurs quite often.)

> •Vel var Þorkatli til stjúpbarna sinna. Guðrún unni Bolla
> mest allra barna sinna. Bolli var nú sextán vetra en
> Þorleikur tuttugu.

> --Well was Thorkatli to stepchild his (ply). Gudhrun
> granted Bolla most of all of his children. To Bolli was
> now sixteen winter but twenty.

<Þorkatli> is the dative of <Þorkell>. This is an
impersonal construction, with no expressed grammatical
subject: ‘[It] was well with Þorkel towards his
stepchildren’, i.e., ‘Þorkel was well-disposed towards his
stepchildren’. <Barna> is the genitive plural of <barn> 'a
child', the gen. being required after <til>; the <-a>
nominal inflection has a few other uses, but all gen.
plurals have it.

<Unni> is from <unna> Z2 'to love' (with the dative of the
person loved), the 3rd sing. past indic. 'loved'. <Bolla>
is therefore a dative, though since <Bolli> is a masc.
n-stem, it has <Bolla> in the gen. and acc. as well.
<Guðrún> is a feminine name.

<Bolli> is nom., not dat.: it’s a masc. n-stem, what Zoëga
(and many others) call a weak masculine noun. <Vetra> is
the gen. plur. of <vetr>, which is indeed 'winter', but
which is also 'year' when ages are being given: one’s age
was counted in winters. It’s literally ‘Bolli was now
sixteen of winters’, but the straightforward translation is
‘Bolli was now sixteen years old’. (The ON sometimes adds
the ‘old’: it could just as well have been <Bolli var nú
sextán vetra gamall>.) At my age it gets a little more
complicated: Ek er fimm vetr hins sjaunda tigar. The
conjunction <en> here is best translated 'and': it has no
real adversative sense.

> --Thorkatli was good to his stepchildren. Gudhrun granted
> Bolla most of his children. He had 16 children in winter,
> but now twenty.

Þorkel was well-disposed towards his stepchildren. Guðrún
loved Bolli most of all her children. Bolli was now sixteen
years [old], and Þorleik twenty.

Brian