At the beginning of the scene, choose a random number in a range(depending on how many possible texts you want to have), and save that to a scene variable. After that, check if the variable is a certain number, then set the text object to have a certain text depending on the number. hope that made sense. If you need more guidance let me know.
PS if you are going to submit a post please try not to make the entire question in the title, just a brief one, and since you are new, consider folloing the template that autogenerates. thanks