Writing by hand requires a child to correctly identify the sticks, curves and/or circles that make up a letter, then reproduce those shapes in a particular orientation, using a set sequence of pen strokes. Before the skill is automatized, the handwriting process can be quite mentally taxing. New writers are also struggling to develop the fine motor skills needed to grip a pen or pencil and the language encoding skills required for reading and spelling.
Add to this the challenge of writing in a straight line and creating letters of the same height and width and you’ll find that reversing letters is a common mistake for beginners to make. This is particularly the case for symbols built from the same set of shapes, including b/d, p/q, f/t, i/j, m/w and n/u. Nonetheless, most children grow out of letter reversal by age 7 and it only becomes a cause for concern when errors occur beyond first and second grade.