I think this is a great project to work on step by step to show the development process. The first step is to get your requirements down. You seem to have a fairly good idea of what you'd actually like to achieve, so that's just about done, but it couldn't hurt to write it down explicitly. We can always revise it later.

Requirements:
1. Create textboxes from array of strings.
2. select text from array in a random fashion
3. configure appearance of created textbox in a random fashion within parameters
4. animate instances with a constrained random speed

What your requirements don't cover is important. For instance, are the y positions of these textboxes random or specified? Should a box loop around once it traverses the entire screen? Is the direction random, right, or left? Where does the array of Strings come from?

We will make some assumptions about these unanswered questions while building our prototype.

The development process continues with the next post.