When we voice slate, you should always use a phonetic alphabet rather than just saying, "aye, bee, see, dee, eee". Many of our letters sound similar and rhyme; which could make them harder to hear, what with the noise on the set and a local accent!

NATO and the military have developed a standardized list of words/names to represent letters. See the attached chart.

Or, if you cannot remember the offical letter call signs -- then feel free to substitute any words or names that would serve the same purpose. No points are deducted for not using the official NATO designators! For example, if you cannot remember that Echo stands for E, you could easily just say Edward.  Or say Frank instead of Foxtrot.

I remember one time on a commercial shoot, long before we all were paranoid about Political Correctness, the editors issued us a challenge to come up with obscene words for every letter of the alphabet!  Probably not a wise thing to do in today's climate, but you can have fun with creating and using your own phonetic alphabet if so desired.

Personally, I prefer to stick with the official one; just one more layer of professionalism.