Put this in your global script:
function SayMessage(int person, int message) {
string buffer;
GetMessageText (message, buffer);
DisplaySpeech(person, buffer);
}
and this in your script header:
import function SayMessage(int , int);
Then you can use the function like
SayMessage(0, 998);
which should make character 0 say 'You run your hands up and down you clothes.' (unless you changed that message of course)