As spoken language evolves we have to eventually adapt the written language. The alternative is written English. That beast managed to incorporate a whole body

As spoken language evolves we have to eventually adapt the written language. The alternative is written English. That beast managed to incorporate a whole body of words from another language without adapting the spelling of those words. It ended in the tears you get every year afresh when you try to teach kids the broken state that is English orthography. The Shavian alphabet is attacking this from the wrong end though. For one thing, we already have a phonetic alphabet. There is no point in inventing another. The main issue though is that you want your alphabet be stable against vowel pronounciation changes. Vowel pronounciation changes quickly and carries little semantic meaning. If you try and encode that in your alphabet it's going to need an update as you move from city to city. The abjad (consonant alphabet) approach of just leaving the vowels as an exercise to the reader may seem a little extreme. It has the distinct advantage of staying stable over centuries though.