It's "My Lullaby" from The Lion King II, in Swedish. I had heard that the lyrics were somewhat disturbing, so I did an amateur translation with the help of Google Translate (no doubt that it got some things completely wrong).
Sweet dreams, little Kovu.
Sleep is falling heavy.
When you become strong and great,
you become a king.
I was kicked out. What he did
was an unforgivable insult.
I remember far more than I should
and that makes me a little cruel.
But I have a dream at night
that provides comfort in all my troubles.
And I'm happy that cats purr
when I dream of Simba's death.
For Simba's very last sound
Claws, which rip his daughter's skin!
His friends' grief and cries of torment -
It's my music!
Well, that's silly to dream
of such a macabre celebration,
but I find it so difficult to forget
death dresses them best.
(Dear Mother, I hear you roar
for one blow at Simba's neck!)
Nuka, the blood may flow,
but it gives me nothing.
A melody of attacking howls,
a requiem for the end of life,
a symphony of death and screams -
that's my music!
I have had a task in my life.
Your training will be good
for a relentless weapon
with pure evil in your blood!
(Sleep well, termite!
I mean, my brother sweet and young!)
(When you become strong and great...)
you become a king!
For the war drums beat mightily.
See Kovu go boldly to the attack.
(Avenging bells!)
(Sweet music!)
The shouts will resound!
(Kovu is unique!)
A blood-red sun shall fall,
a heavenly symbolism
far above Simba's corpse!
It's my music!
Damn Sweden, you scary