The rationale of organising our complex alphabetic code around the sounds which are much smaller in number than their spelling alternatives is a fantastic one for - ORGANISING.
That is PRECISELY why I think Alphabetic Code Charts should be universally adopted - and they can be generic or programme specific - but even a programme specific chart is pretty 'generic' when organised around the principle of listing the phonemes (placed in columns) and the listing the spelling alternatives for those sounds (placed across the rows).
The reason why I then prefer the easy-to-use notation for the sounds is that they can all consist of letters and not additional signs that are part of the International Phonetic Alphabet - which, in effect, can complicate the understanding as one has to get to know those signs.
As I advocate using the notation for the sounds for learners as well - not just adults - then using all letters to notate the sounds (shown in the slash marks) is a very simple way of expressing the sounds.
In addition, the International Phonetic Alphabet is very scientific - very precise - because it is about identifying sounds in speech of all languages and therefore 'common' sounds across the languages come into the picture. It is arguably too precise - therefore inflexible.
But if you use the easy-to-use notation for the sounds (all letter shapes), then it isn't that hard to appreciate that regional accents can be superimposed, or interpreted, onto the notation for the sounds. The variation, in effect, between accents, doesn't matter - just explain to the learners, "In our area, (country, region, locality), we tend to pronounce with words with that spelling like this.....".
On creating Alphabetic Code Charts, however, I found the idea that we have around 42 to 44 sounds very misleading.
This is because some spelling alternatives actually represent units of sound with more than one phoneme such as /k+s/ and /y+oo/.
There is no way around this other than to acknowledge it fully via Alphabetic Code Charts.
There are also some units of sound which do not have to be taught as combined phonemes, but for practical reasons, it might be a good idea such as /k+w/ and /ng+k/, /ul/ and /chu/.
These are choices to be made by programme authors and teachers of course.
All in all, I introduce around 50 units of sound.
This does not mean that there are any more phonemes in the language, just that organising the sounds to spelling alternatives leads to this.
My life aim is to persuade people that Alphabetic Code Charts are as essential, and fundamentally important, as Alphabet Posters, Times Tables Posters, Periodic Tables - that type of information that is truly 'basic' stuff.
It's catching on and I get very positive feedback re use of the Alphabetic Code Charts that are free to download from here:
http://alphabeticcodecharts.com/free_charts.html
Alphabetic Code Charts organised around the sounds are the starting point in the phonics programmes I am associated with - and Raintree (the same company that has published Elizabeth's great non-fiction books) is now promoting the charts (A4 Table Tops) which are being very well-received by teachers, and I've now designed one specifically for the 'Phonics by Phone in Ghana' project which I can describe in greater detail some time in the future.
The work of several phonics programmes/authors underpin much of my work to date - for which I am very grateful.