A is a consonant and i is a vowel ;)
Maybe in Doric, but not in most languages.
I just copy other people. That way, I don't think like an Englishman or like a Pole, but just act like a parrot.
Ach, what are you gibberin on about, donkey?
A is a consonant.
I is often a vowel, but in Polish, sometimes it is a sign that the previous consonant is softened.
As standalone words, a i i (for a a i, i i a, i a a) are similar. I had been treating them as slightly different, but only because I have been copying how the professionals seem to use them. I couldn't quite put my finger on what the exact differences are.