The fact that it's STRONGLY implied that Darkrai have very poor communication and verbal skills due to the social isolation they experience is one of the interesting things about Darkrai that butter my toast.
The few fragmented sentences and somewhat broken English Darkrai speaks in the movie "The Rise of Darkrai" kind of reinforces this in my mind.
Why didn't he just TELL them that Palkia and Dialga were coming? He obviously can talk.
Every time he stepped out, it was on sight for one thing.
Two, he probably has the vocabulary of a middle schooler.
(I wonder if this extends to his reasoning skills as well)
Darkrai: Oh, there's a disaster coming, I need to warn everybody.
Also Darkrai: *causes the most intense and frightening spectrals he can think of, attacks everybody, and scares the crap out of people*
