Q: Would it not be easier to keep the fork in the left hand and the knife in the right and get on with it?
A: It's proper etiquette here in the US. I checked a couple of sites and couldn't find anything specific (I put the link to Emily Post below - that's the standard for etiquette in the US, not sure if it's recognized globally or not). I remember, when I was young, seeing someone from Europe using their utensils the way you suggest and I asked my mother & grandmother about it. I was told (not sure if this is "true" or if they just were trying to shut me up and move on so keep that in mind as you read on) that the way we eat is more civilized and that ill-mannered people don't take the time to put the utensils that they are not using at that moment down before putting the food in their mouth. I also recall etiquette class from Jr High - they really emphasized the fact that holding more than one utensil in your hands WHILE EATING is considered ill-bred (in this case WHILE EATING means when putting the food in your mouth - not when you're cutting or otherwise "manipulating" your food before putting it in your mouth). Since becoming an adult I've traveled throughout Western Europe and the UK on several occasions and found that "they" tend to have much better manners than I see many Americans exhibit on a daily basis so I think that my mother/grandmother's definition of "civilized" was a bit skewed. Personally, I've always wondered if it was a way of showing that we were "independent"... you know, once you got off the boat, you shed some of the ways of the old country and joined ranks. I think that's part of how "American English" came about and always smile when I see words spelled differently (civilized vs civilised; grey vs gray; behaviour vs behavior; etc...) An interesting question... I can't wait to see what others say!