The tonal phonology of Yoruba clitics

This paper examines the tonal behavior of six types of enclitics in Standard Yoruba, and shows that in all six cases, a constraint applies preventing the last syllable of the host and the adjacent clitic syllable from having the same (High or Low) tone. There are no other host + clitic cases in Yoruba for which such a constraint would be relevant. Potential violations of the constraint are avoided by one of five different methods, depending on the case: failure to link a floating tone, deletion of a tone belonging to the clitic, deletion of a tone belonging to the host, insertion of a toneless vowel, or failure to delete an otherwise optional toneless vowel. This pattern is thus a morphophonemic “conspiracy” in the classical sense. However, Yoruba does not have a more general constraint against same-tone sequences in underlying or derived environments.