So, as far as I can tell, Krummi is an Icelandic song by the group Valravn. Here are the original lyrics:

Krummi svaf i klettagjá,
kaldri vetrarnóttu á
:verður margt að meini:

Fyrr en dagur fragur rann,
freðið nefið dregur hann,
:undan stórum steini:

Hammm Hammm

Á sér krummi ýfði stél
Einnig brýndi gogginn vel
:flaug úr fjalla gjótum:

Lítur yfir byggð og bú
Á bæjum fyrr en vaknir hjú
:veifar vængjum skjótum:

Hammm Hammm

Sálaður á síðu lá
sauður feitur garði hjá
:fyrrum frár á velli:

Krúnk krúnk nafnar komið hér
Krúnk krúnk því oss boðin er
:Krás á köldum svelli:

Hammm Hammm

Source: http://lyrics.wikia.com/wiki/Valravn:Krummi

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Here's a translation:

Raven

The raven sleeps on rocky cliffs
On a cold winters night
Many things will hurt him
Many things will hurt him

Before the fair day runs out
He pulls the frostbitten nose
from under a big stone
from under a big stone

Ham Ham?

The raven stiffened his tail
Sharpened his beak as well
Flew from the mountain cracks
Flew from the mountain cracks

He looks over the homes and villages
Before they awaken
He flutters his wings
He flutters his wings

Ham Ham

He lays finished on the plain
A well-fed sheep in a garden close by
Once he was faster
Once he was faster

Craw Craw, namesakes come along!
Craw Craw, there is an offer for
a feast on a cold ground
a feast on a cold ground

Source: http://lyricstranslate.com/en/krummi-raven.html

And here's a YouTube video of Valravn performing the song:

https://www.youtube.com/watch?v=L3NZ-fXeNTw