The single most helpful thing for learning to spell is to read — to read LOTS and lots of books. Seriously. Reading well-written literature is more beneficial to language development (writing, spelling, grammar, etc.) than any language curriculum you’ll ever use with your kids.
I wish people would “get” this … but it’d probably put a lot of curriculum companies out of business if homeschoolers came to understand how good spellers and good writers are actually created. 😉
After fiddling around with a number of different spelling and grammar programs with my older kids, I really started to grasp the fact they truly learned more when we weren’t “doing” spelling or grammar as curriculum per se. I finally learned my lesson … my youngest daughter never had a spelling or grammar lesson in her life (she’s 19 now) and she’s the best speller of the bunch and has a natural, easy (and grammatically correct!) writing style!
If I had it to do over again, I wouldn’t have wasted the time and energy with trying to teach spelling and grammar to any of my kids. Just read, read, read, read, read. And maybe take an afternoon when they’re in high school to go over parts of speech and sentence structure so they can “talk the talk” if they need to at some point. It really doesn’t require years of curriculum and repetition to learn something that they can pick up naturally just through reading for themselves, and then have the “rules” explained to them after they’re already doing it all instinctively.
Just my humble opinion — following a quarter century of homeschooling — for what it’s worth.