Which form to pronounce in casual talk? Is it only black people who pronounce ’a [ə]?

gonna [ˈɡɒnə] gunna [ɡənə] ’unna [ənə] ’na [nə] ’a [ə].

Question

Which form to pronounce in casual talk? Is it only black people who pronounce ’a [ə]?

gonna [ˈɡɒnə] > gunna [ɡənə] > ’unna [ənə] > ’na [nə] > ’a [ə].

Answer

Of the forms you list, “gonna”, which tends to be pronounced “GUNnah”, is probably the most frequently-used form in general casual American speech.  However, depending on the part of the country you are in, you may well hear any of these other forms, as well.  None of them are race-specific.

Answer

don't learn English listening to Ebonics