Since its likely that I won't be adding VO to my map I need to workarround for sudden anouncements. Is there a way to have a popup text appear at times other then at the begging of an objective? Like having a timer at the end of which you get an ambush and a popup text?

ShowObjectiveTextPopup(). It's just an callback that can be assigned to any event. It uses a localize string just like ShowMessageText().

Thank you, by the way, I tried looking through the mygeeto script but I couldn't figure out how the onenterregion command works, could you explain that one please? Namely I just need to set a region that when you enter it you get a text popup.