Looks like an early version of Texting. If the traditional way of learning spelling is considered sub-standard, and I can't think why, it would make more sense to actually use Text spelling as that is already in wide usage and has developed practically rather than something thought up by committee.
I'm surprised to see this from the 60's, I started school in the 70's and only had one set of spelling to learn. We did however learn decimal from age 5 so was a bit disadvantaged when full metrication petered out.
I do wonder how much modern teaching methods like this contribute to dyslexia.
There is a similar issue with Math, we made the error of sending my daughter to a school that taught basic math by introducing many different methods of doing basic calculations, I seem to recall there were at least four ways to do long division. The theory being that different kids would find one method that worked for them. They never really explained this though, and didn't explain how these methods worked or even that the they all produced the same results. This just resulted in confusion from which my daughter never really seemed to recover, her math is now completely erratic, sometimes she flies though it, other times she would fail a times table test.