I am left-handed but was taught to write by the nuns and to only write with the right hand, something about the devil. But in high school with those small desks sometimes I found it advantageous to write with the left hand. I really think writing with the left hand and a fountain pen is just about a bit of training.
My method is a bit off though, I write from right to left with my left hand and left to right with the right hand. I really don't know how I do it, I just see the sentences and paragraphs and write in reverse; my wife thinks writting in reverse is the sign of the devil, but she and my 2yo are lefties too.
"The Communists (Our enemies) will defeat us, not by virtue of their strength, but because of our weakness. They will win by default." Ngô Ğình Diệm