I am tryin to run a dialog while a ship is flying across a background but so far I have only been able to run a dialog and THEN all of the script action or vice versa. This is designed as an intro cutscene and I am trying to do the dialog in the Sierra style with background so the Character.say will not work. Is there any way to do run a dialog at the same time another function is running?
If you just want to have characters talking while other animations/game mechanics are also running, the SayBackground command is your best bet; it displays character speech but allows the rest of the game to continue.
For a multiple-choice dialog, though, you'll have to creak the scene into smaller parts, using run-script commands to trigger additional bits of the cutscene.
Using the global function repeatedly_execute_always it is possible to move stuff on the screen even during blocking commands.
Except if there's a dialog choice GUI on the screen or some text put there by Display("").
So afaik, what you want isn't possible yet.
As a workaround you could emulate the Sierra style speech by using a custom GUI.
If you need just for cutscene another speech style than Sierra, then call in player enters room SetSpeechStyle(eSpeechLucasarts);