Tone, orthographies, and phonological depth in African languages

Marking of tone in African orthographies has historically been a challenge, not
only for linguistic and analytical reasons, but also because most designers of these
orthographies have been educated in non-tonal languages. After a review of lexical
vs. grammatical tone, this paper examines various strategies that have been used
for marking both lexical and grammatical tone in several East and West African
languages, as well as cases in which tone is not marked. The question of the desired
phonological depth of an orthography is discussed, especially when applied
to tonal processes. Many phonologists do not apply theory more recent than Chomsky
and Halle & Chomsky (1968) to orthographies. However, the more recent bifurcation
of rules into lexical and postlexical provides a psycholinguistically supported
phonological level at which tone marking can be based: the output of the
lexical level. Experimental evidence supports this lexical level as more readable
than either a phonemic or a deep level. A tonal typology of languages also guides
what types of languages more predictably would need lexical tone marking. Recommendations
for orthographical implementation are given in the conclusion.