When you give a number that has a zero in it, say a phone numer 555-1010 - do you say zero? Or o (as in alphabet o)?
In Hawaii you must say zero for naught or someone will tell you about how you are mis-dialing by using the alphabet instead of the numbers pad!
Here in New England people use "o" for zero all the time and from context it's easy to tell whether you mean the number or the letter.
Anyone?