Don Osborn, in an email on the a12n-tech mailing list proposed five categories of African languages using the Latin script. These categories are based on the Unicode requirements for representing these languages.
Category 1 orthographies:
ASCII - all characters and combinations covered by the
ASCII character set
Category 2 orthographies:
Latin-1, meaning all characters and combinations covered by characters in
ISO/IEC 8859-1 / Windows 1252
Category 3 orthographies: Extended Latin with no combining diacritics, meaning that the orthographies are covered by the Latin ranges of Unicode without need to use combining diacritics. Here there may be issues with systems for input and available fonts coverage.
Category 4 orthographies: Latin as complex script, meaning the orthographies are covered by Extended-Latin with use of combining diacritics. Here there are issues with input, fonts and rendering that are not encountered in the above.
Category 5 orthographies: Orthographies not fully supported by Unicode, which at this point would mean a missing character (these are probably very few).
Categories 1-3 should be straight forward to implement. Category 4 requires appropriate font rendering and text layout support and appropriate fonts. The following notes, are a substitute for language specific instructions, but should provide a starting point to get you started.
