Magnitude-estimation scaling of speech intelligibility: effects of listeners' experience and semantic-syntactic...

Fifteen speech-language pathologists with extensive experience judging speakers' intelligibility and 15 control subjects with no such previous experience provided magnitude-estimation responses for two sets of nine audiotaped speech samples. These samples were three utterances composed of a group of 17 words that contained all the consonant phonemes of English. These words were arranged to form a set of either meaningful or nonsense utterances. Nine separate versions of both the meaningful and nonsense utterances were created by systematically increasing the number of phonemes produced incorrectly on each of the nine recordings. The analysis indicated no significant difference between the magnitude-estimation scaling responses of experienced and inexperienced listeners. A significant over-all difference was found for listeners' responses to meaningful versus nonsense utterances. The advantages of magnitude-estimation scaling as a measure of speakers' intelligibility are discussed.