I've taught many left-handed people how to knit.. (children included) and I just teach them the right handed way. I can help them better.. and both hands are working together and have important roles in knitting.
It's a little awkward for both left and right handed people.. but, it's an easy skill.. it's not one that requires STRENGTH..
I just taught a left handed friend how to knit a couple of months ago and I even asked her if she wanted to 'try' to figure out what I was doing 'right-handed' and reversing it left-handed.. and she totally wanted to learn how my way.. she's a teacher (school) too and she agreed with me.. that both hands are working together and she said that it's not a difficult skill to learn to poke a stick in a hole and wrap yarn around it.
She has already learned how to do many, many different skills as a knitter.. she's done a lace scarf, a basketweave scarf, working on a cabled scarf right now, and several other knitting skills. She will be moving soon and is learning as much as she can while we are in the same location.