It must be Danish.
Elijah has concluded that the foreign language Viggo is moaning in is definitely Danish. Which is pretty fucking frustrating.
Elijah likes dirty talk. It gives him a thrill. So as he's bent over the kitchen sink, Viggo fucking him from behind, he'd really like to know what Viggo's saying. Something deliciously nasty, he hopes.
And it's pretty fucking frustrating that he can't understand it.
So he cranes his neck around, and glares at Viggo. The other man stops his moaning and looks at Elijah questioningly.
"Dude, speak English!!!"