It's not uncommon for preschoolers and kindergartners to reverse their letters. However, by the time they reach seven years old, they should not make more than just an occasional reversal. If their reversal of letters persists after receiving handwriting help, it could be a sign of a learning disability, like dyslexia, and you may need to request further testing. If it's still in their early years and you notice letter reversal, there are some things you can do to help.
1. Letter Formation
Teach one letter at a time before you introduce a new similar letter. Emphasize how to properly form each letter. For instance, your child should always start a lowercase "b" with a line and the lowercase "d" with a circle. Many children will always start with the line first before they consider the circle. You need to break this habit early by reinforcing the correct formation constantly.
2. Visual Cues
Since the letters "b" and "d" seem to be the most common reversal letters, try using visual cues. For example, you can hold your ringers into a fist with your thumbs up, creating an instant visual cue to help your child know which way each letter goes.
3. Use Multi-Sensory Activities
Some children have a hard time with the fine motor skills required for forming letters properly. Have your child use large motor skills first to focus on proper letter formation. You can have them draw a large version of the letter on a whiteboard or chalkboard or use shaving cream or finger paint to form the letters. Ensure they sound each letter as they form it.
4. Practice Everyday
To help develop new habits, have them practice every day for several days. It only takes five to ten minutes of daily practice to help reinforce the proper formation of letters.
For more ideas, you can talk with your child's pediatric occupational therapist. They can provide you with a list of activities you can do at home to help encourage proper letter formation and avoid letter reversal.