> vowels are denoted by diacritics on the basic consonant symbols: e.g.
> Ethiopic, Indic] and alphabets proper [with both vowels and consonants:
> e.g. Greek]).

How do they justify the division between alphabets proper and abugidas
"syllabarys"? Once you have established that e.g the vowels are
(consistently) diacritics, then why aren't they alphabets? That seems
to require that you have some objective difference between a sign
and a diacritic?

best wishes
Harald