African languages have tone as a characteristic feature. However, tone
is only rarely marked in writing, partly because it makes writing
cumbersome. However, for developing computational applications for
these languages, it is necessary that tone patterns are marked in
writing. Especially such applications as speech analysis and speech
synthesis require overt tone marking of text.
Inserting tone marks to text that originally is without tone marks is a
complicated task, especially in languages that have lexical and
grammatical tones. For example, the final tone pattern of a
verb-form depends on the lexical tone and the grammatical
A general method for tone marking was implemented using Kinyarwanda
language as a test case. A detailed descriptioin of this
system is below.