Importance of various frequencies to perception of continuous discourse

Normal-hearing subjects estimated intelligibility of continous discourse passages spoken by three talkers under various conditions of filtering and noise interference. The relationship between the intelligibility of continuous discourse and the articulation index (transfer function) was different from any found in ANSI S3.5-1969. Also, the lower frequencies were found to be relatively more important for the intelligibility of continuous discourse than for identification of nonsense syllables and other types of speech for which data are available except for synthetic sentences.