and oral channels caused by the imperfect acoustic separation of the channels modules 9 as may other functional systems and subsystems included in and or implemented by various embodiments may be implemented by software hardware firmware and or any combination thereof module 9 may function to implement or cause a subtraction from the measured energy in each channel of a fixed percentage of the measured energy in the other channel this program has as output estimates of the nasal energy 41 and oral energy 42 which are substantially corrected for the crossover of acoustic energy between the nasal and oral channels caused by imperfect acoustic separation but are not corrected for the variations caused by the vowel being spoken correction for the vowel being spoken if it is to be included in this embodiment is performed by program 7 which has as input the energy estimates 41 and 42 fig4 illustrates another embodiment of the invention in which the parameters for the identification of a specific user 39 s vowels are individualized for that user in this embodiment spectral parameters 15 that are used in the identification of the vowel by the program 6 are also output from the program 6 with the user speaking a predetermined vowel these parameters.