The text bubbles are helping a lot. You should still be careful about choosing a color that will contrast with the background, so that it would be easier to read. Or, since each of your characters seems to speak in a distinct color, you could change the color of the text bubble itself so that it contrast with the color of the text.
Still, it's already much better!
I took a quick glance at your archives. You have some really nice drawings in there. I like it :P