The international alphabet is a useful tool when communicating over a radio or phone, e.g., between a pilot and control tower. I am often misunderstood when I relay information over the telephone so I keep an international alphabet cheat sheet in my desk which definitely comes in handy and I always have the person verify the information before getting off the phone.
Source: Fry, E.B., Ph.D. & Kress, J.E., Ed.D. (2006). The Reading Teacher’s Book of Lists 5th Edition. San Francisco, CA: Jossey Bass.