Abstract: Populations with special auditory problems in large areas have been investigated. They are called non-"normal" listeners. There are at least three categories such non-"normal" listeners:
a. the hearing-impaired listener
b. the middle and older-aged listener
c. the listener for whom the talker’s language （or accent or dialect） are different from that of his early childhood. Some research results about their specialauditory problems have been expounded, such as effects of increasing the speech-time fraction in interrupted speech, relationship between age and reverberation time, effects of different language, accent, dialect, etc.