Phonetic Alphabets
Phonetic alphabets can be used to reduce between-letter confusability
and improve performance for both human-human and computer-human
communication. This is particularly the case for situations where the
contents of a communication provide little constraint on possible word
sequences.
In the course of the CRUISER project, we had occasion to observe
actual usage for a phonetic alphabet on the indexing channel used by
the Pittsburgh City Police. Collection of samples took place during
the summer of 1996 and consisted of observing the process from both
the indexer's station and the officer's car during actual patrols. We
also asked several officers to recite the alphabet as they normally
used it and asked about any variations they may have encountered in
their work. The materials we collected by no means capture all
possible variations in the Pittsburgh environment, though we do
believe that they are representative of the most common usage. We
should emphasize that our goal was to gather a representative sample
of usage rather than to exhaustively document the language patterns
used by the police.
Some observations:
- A great many police officers in Pittsburgh (and we suspect
elsewhere) come from a prior career in the military. As a result of
this background all are familiar with the "military" phonetic
alphabet and use it reasonably consistently.
- Some officers come from jurisdictions that ask officers to use a
specific alphabet, typically described as a "police" or "civilian"
alphabet. The one such alphabet we collected was similar to
published
police alphabets and appears to be distinguished primarily by the
greater use of personal names.
- In actual use, there appears to be little consistency in the
choice of words (although a phonetic style is always used). Primarily
officers appear to improvise on the theme of first names. This does
not seem to have any detrimental effect on communication quality (that
a word is likely a name is probably sufficient constraint).
- We were informed by a supervisor in the EOC that Pittsburgh had
two official phonetic alphabets, however we were unable to obtain
copies of these. One of these would almost certainly be the Military
alphabet.
The Pittsburgh Police Phonetic Alphabet (summer 1996)
| Alpha | Apple | Adam | Albert |
| Bravo | Boy | | |
| Charlie | Charles | | |
| Delta | David | | |
| Echo | Edward | | |
| Foxtrot | Fox | Frank | Ford |
| Golf | Gary | George | |
| Hotel | Harry | Henry | |
| India | Indigo | Ida | |
| Juliet | John | James | |
| Kilo | Kevin | King | |
| Lima | Lincoln | Larry | |
| Mike | Mary | | |
| November | Nancy | Nora | |
| Oscar | Ocean | October | |
| Papa | Paul | | |
| Quebec | Queen | | |
| Romeo | Robert | | |
| Sierra | Sam | | |
| Tango | Tom | | |
| Uniform | Union | | |
| Victor | | | |
| Whiskey | William | | |
| X-ray | | | |
| Yankee | Yellow | Young | |
| Zulu | Zebra | | |
Notes:
- The first entry on a line is the Military letter. It is not
necessarily the most frequent word observed in use (our sample would
be insufficient to establish true frequencies). At the time of
collection, the letter A was the most frequent letter in local license
plates (O, Q and I the least frequent).
- Although officers claimed to know the military alphabet, we did
not actually observe anyone use the word Quebec, even in
recitation. Queen was the unanimous alternative.
- While Zulu showed up in recitation, Zebra was the only word
observed in actual use.