Jim, I learned he Phonetic Alphabet when studying Phonetics as an 'extra' subject at Uni. It's very useful, as you say, for transcribing speech accurately. But it can come unstuck as it depends on the ears of the listener. For example, when I did exercises alongside other students, we each heard different things, eg breathiness on vowels, fricative or plosive, voiced/unvoiced. It got more and more complex. You're right in that the spelling of speech is very misleading, even when writing English from different parts of the world. I loved the book about 'Strine' for example, (Australian) which tries to 'spell as it sounds'.