2007. Endangered Languages in Central Africa.

2003. with Zeitlyn, David. Ethnogenesis and fractal history on an African frontier: mambila–njerep–mandulu

2002. Tone languages and the universality of intrinsic F0: evidence from Africa. 2002. with Ahoua, Firmin & Gibbon, Dafydd. Ega

2001. Downdrift, Downstep, and Declination.

2000. The Perception of Lexical Tone in Mambila.

2000. with Richard J. Hayward, John Abraha Ashkaba. Observations on Kunama tone. with John Hajek (undated).  Universals of nasal attrition

1999. A Preliminary Report On Pitch Realization”

1997. Moribund Languages of the Nigeria-Cameroon Borderland. Symposium on Language Endangerment in Africa;

1995. with Amalia Arvaniti. Phonology and phonetic evidence.

1990. with D. Robert Ladd. Aspects of pitch realisation in Yoruba.

1983. with Hogan J.T.; Rozsypal A.J. Experimental evidence of interaction between tone and intonation in mandarin Chinese