@hacks4pancakes I’ve heard different explanations for this which tie the switch to westward American expansion, where Americans gave up the knife altogether and used the fork sideways as a cutting instrument - this allowed them to eliminate carrying one knife for every fork on the wagon trains, thereby cutting down on weight. No idea if there is truth to this or not.

It took 2 years for me to learn how to use the fork in my left hand and knife in my right after moving to Portugal! My kid, who was five when she came here, kept calling it out (she learned to eat the European way in the canteen at school where they make the kids hold the knife and fork in this manner) so my wife and I had to adapt