Abstract: A hearing aid having a comparator or comparators which compare speech sound signals obtained by a first transducer with reference voltage(s) as slice level(s) formed from a standard voltage and which output time series square wave containing frequency information according to the relations of amplitude between the speech sound signals and the slice level(s).The time series square wave is output as mechanical vibrations, which is easy to adjust the level for hearing impaired persons having a narrow dynamic range.Comparators may be provided for both positive and negative sides and may be divided into plural numbers in order to raise the identification score and information content.

Abstract: A method of measuring the degree of nasality in human voice sounds by independently isolating and measuring without leakage the exhaled air flow rate through the nose and the exhaled air flow rate through the mouth of a person resulting from the utterance of a sound and determining the ratio of the two air flow rates.

Abstract: An electropalatograph wherein a plurality of signal-transmitting electrodes on an artificial palate for detecting linguapalatal contact pattern are scanned sequentially in a predetermined order with a series of scanning signals, transmitted signals from actually contacted ones of the signal-transmitting electrodes to a single signal-receiving electrode on the artificial palate and contacting with the user's hard palate are sequentially detected by a single detector, and detected signals identifying the actually contacted electrodes are employed to dynamically indicate the pattern. To increase detection accuracy, the detected signals are compared with standard linguapalatal contact data, optionally with a modification of such data to provide an allowance in accuracy determination.