International Civil Aviation Organization (ICAO) alphabet (also known as the international radiotelephony spelling alphabet and incorrectly as the NATO phonetic alphabet), Morse Code, and Signal Flags.

Word
Morse
Signal Flag
Word
Morse

Alfa
. -

Zero
- – – – -

Bravo
- . . .

One
. – – – -

Charlie
- . – .

Two
. . – – -

Delta
- . .

Three
. . . – -

Echo
.

Four
. . . . [...]