I'm going to try to translate this.

me tel u now so u belive me 15 may
many things go wrong 15 may because door opens with portal to dark matters not undestanding earth beings
sharon will dimise be4 15 may
mandela will dimise be4 15 may
thatcher will stroke be4 15 may
japan warring thing will commencecing before 15 may secretely
oil gets very big sickness no use anymore after 15 may
old bush will very sick be4 15 may
cheney will dimise be4 15 june
obama accident before 27 aperil
big sickeness be4 15 may
very moving earth on 17 aperils
oceone not sleeping when heaven things beware many waters to come drown
brown cheat be4 15 may
putin missing after 15 may many worry poeple do crazy things

That's the original. Now let's see what we can find.

I will tell you now, so on May 15th, you believe me.
On May 15th, doors open with a portal from dark matter, many things go wrong.
Humans aren't capable of handling dark matter.
Sharon will die before May 15th.
Mandela will die before May 15th.
Thatcher will have a stroke before May 15th.
Japan will be in war before May 15th secretly.
Oil becomes very toxic, no one uses it or seafish from the oil spill before May 15th.
Old Bush AKA George W Bush sr, very sick before may 15th.
Cheney will die before June 15th.
Obama will have some sort of accident before April 27th.
A big sickness before May 15th, a pandemic maybe? The China has that flu going around right now, could be that?
On April 17th, Earth will move a lot, maybe an earthquake or some sort of Earth shake?
The ocean isn't sleeping when heaven things beware (possibly the moon will influence), water will either rain and cause massive floods or a tidal wave.
Brown will cheat before May 15th.
Putin is missing after May 15th, people become very hostile and start doing radical things/ chaos.