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Computer readable phonetic alphabets

The phonetic alphabet of the IPA is the most commonly used alphabet for the phonetic representation of all spoken languages of the world. It is based on the Latin alphabet, which allowed it to be printed in any better printshop by using the common lead characters.

The code tables for characters in computers have been restricted to 256 entries which could be addressed using one byte, i.e. 8 bits. These code tables are too small to accommodate the full IPA alphabet together with a standard alphabet. Furthermore, IPA characters are often composed of other Latin characters, resulting in a mapping problem: A 1:1 mapping of code table entry to character does not fit into one-byte code tables and requires redundant definitions of font, size, and case operations, whereas composition rules for the combination of base symbols to give an IPA alphabet character are not allowed in many operating systems and thus require proprietary solutions, which make porting a document to another platform almost impossible.

A pragmatic solution to this problem was either to

The first approach is chosen in SAMPA, where language dependent subsets of the IPA fit into the US-ASCII code table. The second approach is taken in KLATTBET, TIMBET, MRPA, IPA numbers, and others.

With multi-byte alphabets now in the process of standardisation, a direct representation of the IPA alphabet on the level of the operating system has become possible. However, there is still the problem of backwards compatibility, i.e. accessing documents that use a particular one-byte coding system or a proprietary nomenclature.





next up previous contents index
Next: IPA subsets Up: Character codes and computer Previous: MIME

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