Dual channel signal analysis of oral and nasal consonants

In this study we captured oral and nasal signals using a close-talk, head-worn condenser microphone and a contact microphone on the nose. Native speakers of Assamese with no history of any speech disorder were recorded reading three English passages containing phonetically balanced nasal and oral consonants (Rainbow passage), a second passage containing primarily nasal consonants (Nasal passage) and a third passage containing no nasal consonants at all (Zoo passage). Differences between the normalized intensity of signals obtained from the nasal channel and the oral channel (d
n
) were plotted. The plots indicated higher peaks at the location of the consonants. As expected, nasal consonants had higher peaks compared to non-nasal consonants. From these observations, an attempt was made to detect consonants in continuous speech. Apart from that, average d
n
values among the three types of passages were compared.