I don’t tell my kids that there are any *rules* in particular. I tell them that letters are sound pictures. They represent the sounds that *we* make. For example: I tell them that the sound picture (or combination of sound pictures) can represent several different sounds. When they struggle with spelling or reading a new word we go over (either by memory or by resources we have) the *possibilities* the sound picture(s) could represent. I rarely help them with reading, once they have basic skills, and cause them to segment it out themselves. Spelling for my 7yods is still being worked on, but boy has his reading taken off in a big way.
I know this doesn’t make perfect sense, but it works, or at least it is working in our hs. My kids understand what I’m saying when I say it, so I guess that’s all that matters.
Oh, also, I don’t tell my kids that certain letters/sound pictures are silent. I tell them that they do not represent an extra sound, but are used in the spelling of the word. When they ask WHY I tell them I don’t know, and that somewhere in time it was decided that that is how that word would be represented. I also tell them that without a particular letter/sound picture not only would the word be spelled wrong but it could actually spell something else.
I have two 6yo’s that I’m teaching right now so we’re not doing “formal” spelling. However my now 19yo went through a few years of spelling workbooks by various publishers. He made 100’s on every single test but couldn’t spell worth a flip in his everyday writing. It drove him NUTS when a word didn’t go along with the “rule” which was most of them. (He’s the math/science genius type. ) I finally pitched all the spelling books. We read a lot anyway, did copywork, dictation, etc. He spells pretty well now. I plan to use Spelling Wisdom with my little guys in a couple of years.