Spelling alphabet

A spelling alphabet (also called by various other names) is a set of words used to represent the letters of an alphabet in oral communication, especially over a two-way radio or telephone. The words chosen to represent the letters sound sufficiently different from each other to clearly differentiate them. This avoids any confusion that could easily otherwise result from the names of letters that sound similar, except for some small difference easily missed or easily degraded by the imperfect sound quality of the apparatus. For example, in the Latin alphabet, the letters B, P, and D ("bee", "pee" and "dee") sound similar and could easily be confused, but the words "bravo", "papa" and "delta" sound completely different, making confusion unlikely.

Any suitable words can be used in the moment, making this form of communication easy even for people not trained on any particular standardized spelling alphabet. For example, it is common to hear a nonce form like "A as in 'apple', D as in 'dog', P as in 'paper'" over the telephone in customer support contexts. However, to gain the advantages of standardization in contexts involving trained persons, a standard version can be convened by an organization. Many (loosely or strictly) standardized spelling alphabets exist, mostly owing to historical siloization, where each organization simply created its own. International air travel created a need for a worldwide standard.

Today the most widely known spelling alphabet is the ICAO International Radiotelephony Spelling Alphabet, also known as the NATO phonetic alphabet, which is used for Roman letters. Spelling alphabets also exist for Greek and for Russian.