All to do with a part of the brain called Broca's area which in 90% of cases is on the left side (left hemisphere) and is responsible for speech, writing and right or left handedness.
If you are right handed then Broca's area is on the left of the brain, if you are left handed this area is on the right side of the brain.
Trying to make a left handed person to write right handed makes him/her stutter.....because of the above.
Pierre Paul Broca....that's all i know about him.