theres a skill name "Dual Wield Expertise" it enables u to wield 2 weapons of the same kind.
You can get this on:
Sword Master- lvl 10
Magnus- lvl 5
Blade Taker- lvl 10
Temper Master- lvl 5
note: u need to use weapons of the same kind to dual wield (ex. 2 daggers, 2 swords, 2 mace and 2 axe)
-you cant dual wield one-hand staffs-
edited: Temper Master- lvl 10 -> lvl 5