There have been speculations among scholars in the past on the reason for the perceptible difference in the tonal pattern of the Abankeleke Igbo. Prominent among these is that there is a feature of the upstep tone in this dialect group especially in Izii and Ezaa dialects that is absent in most other Igbo dialects. This paper therefore sets out to investigate the truth or otherwise of this claim in Izii and Ezaa dialects by analyzing the tone levels operational in these dialects and in the Standard Igbo and to compare them with those of the Standard Igbo. The data are collected through personal interview. Three respondents are randomly selected; one for Izii, Ezaa and Standard Igbo respectively. An adapted version of the Ibadan wordlist of 400 Basic Items was used and the data were recorded electronically. The data were transcribed and analyzed electronically using the Speech Tools Analyzer version 3, 0.1 (1996-2007) and the Phonology Assistant version 2.2 (1995-2005) software packages developed by the Summer Institute of Linguistics (SIL) International. The result of the perceptual analysis, which is confirmed by the instrumental analysis reveals that there is a feature of the high raising tone in Izii and Ezaa which is absent in most other Igbo dialects (among other factors) that contributes to the peculiar tonal phenomenon perceptible in the speech form of this dialect group.
Keywords: Acoustic analysis, Dialect, Pitch, Speech form, Tone