You’re right about lots of the things you say in this posting. Spelling does ‘bug’ lots of people. It is accorded far too much importance partly because it is seen as a transparent marker of a person’s educational attainment or even intellectual ability. And so we become trapped in the poor speller/good speller binary, with each generating a range of negative/positive connotations on each side of the divide.
As one dad to another, your attitude towards your daughters seems exemplary. The sentence ‘a see cretur finds a shel’ is the kind of spelling any YR/beginning of Y1 teacher would be proud of. However, as you say, you wouldn’t be very happy if your daughters were in Y11 and still spelling like that. Leaving aside the issue of the grammar (children know something like around two-thirds of the grammar of the language by age 5), you are quite right in thinking that they will be subject to various approaches to the teaching of spelling as they progress through school. This is because, in the main, most primary teachers don’t understand the spelling system and how it relates to the sounds of the language.
Funnily enough, it’s interesting that you employ the simile of the hydra, for it was the hydra that, in Greek mythology, guarded Lake Lerna and it provides us with a possible analogy for the spelling system. In the days of yore, before the arrival of Thor Nogson, the Normans, the incorporation of all our Latinate and Greek spellings, and so on, we had a relatively simple system – pretty much one way of spelling a sound. As Anglo Saxon heads were severed by our invaders, the spelling hydra’s heads multiplied: instead of one spelling for a sound, there grew to be many.
However, times have changed and instead of the post-Potter generations wanting to kill the hydra, as we might have wanted in our beastly past, we can now take it to our bosoms as a pet and utilise it to teach our children the way the writing system is a code for the sounds in our very versatile language.
So, how does it work? First and foremost, you need to teach those daughters of yours that the spellings stand for sounds in the language and you should be working on the one letter spellings-one sound to begin with. Afterwards, move on to teach two letters one sound in the context of words with ff ll ss and zz (‘huff’, ‘well’, ‘miss’ and ‘buzz’) at the end.
Now for the hydra! The hydra is the reason no-one can be a perfect speller, which incidentally puts us all in good company. How would one know how to spell a word which has many syllables, some containing less frequent spellings, if one had never seen it before? This is the major stumbling block for most learners: no-one tells them explicitly that there are multiple ways of spelling sounds in the language, never mind teaches them which spellings spell which sounds.
So, here’s what to do. You can put up little charts on the wall with each head of the hydra (or an octopus, or a tree – there are many possible models) representing a spelling of a particular sound, thus grounding the spellings in the sounds of the language, which remain constant and don’t change. Here’s an example of my /ae/ (as in ‘play’) hydra.
So, how would this work for your daughter’s sentence? Well, I’d leave the word ‘creature’ alone until they’re a little more experienced but I’d say that the way we spell the /ee/ in ‘sea’ is like this (pointing to the word on your chart with that spelling. With 'shel' you say, "This," pointing to the letter l "is a way of spelling /l/ but in this word we need this spelling." And now you write the double l spelling for her. That way, you make clear that all sounds can be spelled and you also make your daughters analytical into the bargain. This is exactly how I dealt with spellings my own daughter had problems with and it works at any and all levels. For your Y11s, you should never give them the whole word unless it contains so many complexities that it will overwhelm them.Fortunately, there really aren’t that many. Here’s another example: in Year 5, my daughter once asked me how to spell ‘archaeology’. I asked her what the difficult spelling for her was and she told me it was the sound /ee/. I simply said that the sound /ee/ was spelled ae. That was it!
Of course, there’s much more to teaching children how to read and spell but if there's one thing worth keeping in mind it's they are two sides of the same coin and should be taught together from simple to more complex.