Very true, KZS. It is at such a time as this that you have to miss the late Dr. Valentine Ojo, the polyglot.
What Soyinka called "tonality" is an attribute of all musical languages, of which Yoruba is one. A good number of West African languages fall in that category. The late lingust, Kay Williamson, talked a lot about that, and the first person to pay good attention to that fact in Yoruba is David L. Olmstead of the University of California, Davis, who wrote on what he called "toneme" in Yoruba back in 1958. In the ears of non-native speakers, Yoruba sounds like music.
The problem that WS stresses in that conversation is that when people confuse tones in each of the syllables of the language, confusion steps in because the result may be a complete opposite of the intended outcome. This is even worse when singing some of the popular English songs and hymns in Yoruba, rendering them in the translated format and imposing the existing English sound on them. Take for example, the popular Chrismas Carol, "O come all ye faithful" when translated into Yoruba comes as "Wa eyin olooto." If the song is now rendered exactly in the musical notation of the original English version, in the ears of someone who never heard the English version before, say someone like my grandmother who never went to school, or a child exposed to only the Yoruba language, it would translate as "Dig up or sift the palm fruit all you masters of urination." How different is that meaning when compared to the intended "O come all ye faithful"? They are one light year apart!
You see, musicology and tonology are two concepts that musicians and listeners of the Yoruba music must pay attention to, and that is all Professor Soyinka was saying in his discourse of the Àpáta, Alápáta, Alàpáta Alápatà continuum. The first one means the rock, the second one means owner of the rock, the third means a blaster of the rock, and the fourth one means a butcher. It makes the language quite interesting and a gold mine for poets and eloquent speakers like the late politician, Oladoke Akintola of the 1960s. In the same vein, if you put different tones on the word that spells as "I-g-b-a" in Yoruba you could end up with unrelated meanings such as "calabash" "time" "garden eggs" "200" "Harness for climbing the palm tree" etc. In essence, a lack of knowledge of the tonal process would only produce nothing but a Tower of Babel!
Michael O. Afolayan
From the Land of Lincoln