Mælti döggla deilir
dáðum rakkr, sá er háði
bjartr með beztu hjarta
benrögn, faðir Högna;

"The bright sharer of rings(?), = Högni's father (i.e. Gunnar), bold
in deeds, who gave battle with great spirit /courage, spoke (thus):"

From the context, 'döggla deilir' must be a kenning for "man".
*'döggull' is otherwise unrecorded, but according to one theory, it
might mean "ring", or some such precious object (from the idea of
"dew" or condensation forming on the shiny metal?). An alternative
explanation is that the word is actually *'daugull' "the
hidden/secret", cognate with Old English 'déagol' (which readers of
The Lord of the Rings might recognise...), from the idea of buried
treasure? 'au' and 'ö' are used interchangeably in manuscripts of the
time.

'háði', preterite 3rd person sg. of 'heyja' "to give/conduct [battle]".

'með beztu hjarta' "with the best heart", i.e. "with the greatest of
courage", "with very fine spirit".

'ben-rögn', neuter plural of 'ben-ragn', is "wound-goddesses" (rather
than 'benregn' "wound rain", which would also make a kenning for
battle). The idea is that, since 'Hildr' is the name of a valkyrie as
well as being an ordinary noun meaning "battle", any other way of
referring to valkyries can be used to refer to battle!

heldr kvazk hjálmi faldinn
hjörþilju sjá vilja
vættidraugr en vægja,
val-Freyju stafr, deyja,
val-Freyju stafr, deyja.

"This helm-clad wielding-trunk of the sword-plank (=the trunk who
wields a shield = the warrior = Gunnar), said that he'd rather die
than yield, oh stave of the goddess of the slain (=stave of Hildr =
warrior)."

Again, here's a play on words with a kenning for valkyrie (val-Freyja)
being used with the meaning "battle". Both kennings for "man/warrior"
use as their base word a term for some kind of wooden object; this is
just the usual convention whereby trees or other bits of wood are used
as the base word in kennings for men or women depending on the
grammatical gender of the wooden object, although it might be no
accident that 'draugr' "trunk" is used here, since this word also
means a dead man and the verse is spoken by a dead man.

'hjör-þilja' "sword-plank", a kenning for "shield".

heldr 'kvazk' / 'kvaðst' vilja deyja en... (kvað + the reflexive
suffix): "said that he would rather die than..."

'vægja' "yield"

The warrior addressed could be Skarpheðinn or Högni; there's no
indication which. That's the usual interpretation, anyway;
alternatively, the kennings for man might be in apposition, both
referring to Gunnar. This was the opinion of E. A. Kock, but the ÍF
notes add that such repetition (and repetition of the repetition)
might be said to be redundant / overdoing it [
http://www.usask.ca/english/icelanders/proverbs_BNS.html ]. They also
observe that the repetition of the final line is a common feature in
'draugavísur', verses attributed to the dead.

LN