Cas talks in his sleep.

File that under the list of "Things Dean Winchester never thought he'd learn," but here he was, laying next to the scruffy angel, hearing his soft, even breathing. Every few moments the angel's gentle breathing was broken by a few muttered words, maybe half a sentence.

Among them were gentle grunts, half-assed attempts at forming syllables through the soft fog of sleep.

Mostly, though, Cas reverts to Enochian. And even though Dean can't understand the ancient whispers, he still listens.

Because between the grunts, and the breathing, and the gentle snores, and the phrases of broken Enochian, if Dean's listening, he'll always hear his name.