 Re: Alveolar plosive, and alveolar stop also.
The sound you're talking about is called the yod, and it's IPA symbol is/j/ - but you're right in everything you say about it. The change you're talking about is called yod coalescence, so the pronunciation of the words in your examples might be :
about you : /əbaʊt juː/ or /əbaʊːʧuː/
not yet : /nɒt jet/ or /nɒʧet/
cooked yet: /kʊkt jet/ or /kʊkʧet/
And as an example of yod coalescence with a /d/ sound , the final two words in Have you heard yet? could be /hɜːd jet/ or /hɜːʤet/ |