Who can i do a dialogue in a multiplayer scenario?

[jmps]

Hello, I´m making a new multiplayer scenario and i´d like know who can i do the following message in the scenario:"I cannot believe what my eyes are seeing! The flesh runs from their bones... these are not orc warriors we fight. They are evil spirits masquerading as orcs!".
I want a hero speak these message, a random hero (the hero can be a human,dwarft,bandit,elf,...)which the computer or the human player assigns in each game, the hero is the side=1 (the player 1), and these message is in the turn 4.
In the scenario.cfg archive I write:
[event]
name=turn 4
[message]
speaker=?????
message= _ "I cannot believe what my eyes are seeing! The flesh runs from their bones... these are not orc warriors we fight. They are evil spirits masquerading as orcs!"
[/message]
[/event]

?????= What does i should to write here?

Can you help me, please? Bye.
(Note: I´m sorry for my English,it is very poor)

[A Guy]

You don't use speaker=, you use the StandardUnitFilter inside.

[Turuk]

Moved to WML Workshop.