AN AUTOSEGMENTAL ACCOUNT OF GLIDES IN IGBO TONOLOGY

Abstract

For several decades, scholars have tried to develop theories that can
account for phonological issues in human language. The autosegmental 
phonology model of Goldsmith (1976) is one of such theories. Igbo is a 
register tone language where tones are essentially level (Anagbogu, Mbah 
and Eme, 2001: 97). There are three tones in Igbo – high tone represented 
with an acute accent /´/, low tone represented with grave accent /`/ and 
down-step tone represented with a macron /‾/ orthographically and a 
down arrow, followed by an acute accent /↓/ phonemically. Igwe (1975) 
observes that in speech, these tones tend to be phonetically motivated to 
glide in Igbo. To Eme (2008), this phenomenon is an evidence of a 
lengthened vowel or two identical vowels with contrasting high and low 
pitches, while Mbah and Mbah (2010) describe it as being a result of
‘graphological elision’. This paper agrees with Igwe (1975) and uses the 
autosegmental phonology model of Goldsmith (1976) to account for this 
kind of behaviour. The tone gliding in Igbo manifests in two ways – rising 
tone / ᵕ / and falling tone /ᵔ/. It occurs in speech in the language when two adjacent identical vowel sounds or lengthened vowel sounds are not of the same pitch. This paper has demonstrated that in addition to the descriptive approach usually adopted in past literature in describing tones in Igbo, autosegmental phonology model has conveniently handled the issue of glides in Igbo tonology. It is certainly an improvement on the past studies and a challenge to study other aspects of Igbo phonology using the autosegmental phonology model.