The explanation that kogi is pronounced like yogi implied to me, limited being that I am, that the 'g' was a so-called hard consonant, not that the vowel sounded like 'oh'.
But yes, that does assume American English pronunciation (and for what I know, various other Englishes too).
There are multiple phonemes often represented by the letter a; the GP is asking which of those is correct.
Edit: all of these assume American English pronunciations.