“A 'ISO” where that apostrophe represents hard attack on the vowel sound.
As for what that is, consider the phrase “Paula asked a question.”
If enunciated clearly there’ll be a hard attack between “Paula” and “asked”.
(In this example, some — chiefly British — people will put an R sound between them if they don’t enunciate clearly. The R wouldn’t show up in “A ISO”, but this is to demonstrate hard attack, not get into those weeds.)
“A 'ISO” where that apostrophe represents hard attack on the vowel sound.
As for what that is, consider the phrase “Paula asked a question.”
If enunciated clearly there’ll be a hard attack between “Paula” and “asked”.
(In this example, some — chiefly British — people will put an R sound between them if they don’t enunciate clearly. The R wouldn’t show up in “A ISO”, but this is to demonstrate hard attack, not get into those weeds.)