I'm left handed, but I knit right handed, English style. If someone is truly knitting left handed their stitches are going from the right hand needle to the left hand needle. I never could wrap my head around left handed knitting, even though in most things I'm VERY left dominant.
I suppose your teacher could be doing some kind of variation though. The person who taught me was right handed, but she ALWAYS knit into the back of the loop, and it took several years before I figured out why I had crossed stockinette and not the nice smooth VVVV.
Variety may be the spice of life, but every now and then bland is OK.