Further to the issue of " childlike documents" - Banks' wording here is significant. Something "childlike" is, by definition, something produced by someone who is NOT a child, just as "cat-like movements" are those of a being other than a cat. So we can rule out real children here; Banks would have used "childish" or "child's" if he were referring to something he actually believed was drawn or written by a child.
With respect to the printing vs cursive issue, French schools in France, and the Toronto French School here, do not teach young children printing. They are taught a French cursive script from the beginning, starting in Kindergarten. So DM probably never learned to print properly in English, and his cursive would look strange at best, as the letter formations are different and so are the joins.
