Development of a test of speech intelligibility in noise using sentence materials with controlled word predictability

This paper describes a test of everyday speech reception, in which a listener’s utilization of the linguistic-situational information of speech is assessed, and is compared with the utilization of acoustic-phonetic information. The test items are sentences which are presented in babble-type noise, and the listener response is the final word in the sentence (the key word) which is always a monosyllabic noun. Two types of sentences are used: high-predictability items for which the key word is somewhat predictable from the context, and low-predictability items for which the final word cannot be predicted from the context. Both types are included in several 50-item forms of the test, which are balanced for intelligibility, key-word familiarity and predictability, phonetic content, and length. Performance of normally hearing listeners for various signal-to-noise ratios shows significantly different functions for low- and high-predictability items. The potential applications of this test, particularly in the assessment of speech reception in the hearing impaired, are discussed.