I'm a leftie as are DH and DS1.
Tbh, pretty much the only thing I do with my left hand is write and I'm crap at that (oh, I do chop veg as well). I discovered the slanting page technique only ten or so years ago when I was looking for ways to help DS. He was then about 8 or 9 and refused to have anything to do with any of the props as he said there was nothing wrong with him
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Sorry to be the one saying this but I actually wish I'd been encouraged to use my right hand. I have had bad handwriting all my life which caused excruciating embarrassment when I was studying and training to become a designer - but, try as I might, it just wouldn't come out as anything other than random scribble (I do maintain it's perfectly legible, though).
Reason I regret my southpaw-ness is it actually causes me physical pain- it literally goes against the grain to be pushing the pen away from you, working against the natural motion of the body. Comfortable writing for a left hander would be right to left (mirror writing, obv), which just can't be done in our society.
I have scoliosis and constant shoulder pain, aggravated when I use the arm to write (or chop!). Feel free to write me off as a crank - just wanted to put the other side.
Fwiw, I'm really glad I learned to do most things right-handed; it's not difficult to learn to knit or play an instrument by mimicking the actions. Never even occured to me to get DS to play guitar left-handed.
Tethers, there's absolutely no need to teach your DD to eat the wrong way round - it's easier for lefties to hold the fork in their left hand!