My first grader has the hardest time with these three. (I remember my now fourth grader having the same problem in K and 1st) So, I'm going to try with him, the same thing I tried with my first child. It took time, but it worked.
I cut a capital and lower case of each letter out of felt, glued them to an index card and had my student trace over them with his finger while saying the letter. I have also done it with rice on a cookie sheet and sand in a cake pan. Anything tactile. I have also heard of people using fine grit sandpaper to make the letters.
I don't know how long it took for my first child to recognize the difference, but it did eventually happen. I do know that my method of saying, "No, no honey, that's a diver letter not a magic c letter." is not helping him recognize the difference. [If you are confused by that last statement, you must not use Handwriting Without Tears - which, by the way, I highly recommend for hand printing]
So, starting tomorrow, I go back to the old tactile & auditory method. I'll let you know how long it takes till he gets his b,d and p's right. I'm hoping it doesn't take long. My poor little guy needs more confidence in reading, and these three letters are definitely not giving him that.
I sticky-tacked them to his desk for reference and practice throughout the school day.
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*9-1-11 - He did great with the letters on his desk. I don't know why, but he read almost flawlessly (and there were a lot of b, d & p words) without looking at his prompts much. I had him trace them with his finger before reading. I know it was a 1st try and next time could be different. I'll update in a week.
*9-20-11 - Ok, so it's been over a week...Sorry bout that. - I have not been faithful with making him trace his fingers over the letters everyday, but I have made him do it when I remember. I have noticed with the little amount that I have done it and having the letters stuck to his desk for him to see at all times, he has confused b,d & p much less than he had before. Now if I can just have him to do it regularly, I think he'll benefit from it greatly. I'd better get on the ball!