“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.)
How do those dialects pronounce it, a yeeso?
“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.)