I wanted to choose a colour for Ginny's speech bubbles that was something like her hair or clothing. I always try to match the speech bubble colour to some aspect of the character, if I can. The trouble was Monty and his father have colours in the beige-to-pink region, and there wasn't a lot of room in between. But I gave Ginny the orange colour since the alternative would be something a lot more green or blue, which would clash rather badly.

So Ginny's dialogue is in a hue exactly midway between Monty's and Professor Jones'. I hope it's different enough to be easily distinguishable.