DECtalk and VeriVox: intelligibility, likeability, and rate preference differences for four listener groups.

The intelligibility, likeability, and speech presentation rates for two types of popular synthesized speech, DECtalk and VeriVox, were investigated across four age groups ranging from 6-85 years old. Results for all age groups revealed differences in intelligibility between synthesized adult and child voices, with intelligibility scores for child synthesized voices significantly below those for adult synthesized voices. The most popular synthesized voices were from the VeriVox family. Of interest is that preferred speech presentation rate, expressed as mean words per minute, increased as a function of age, with the oldest listeners preferring the fastest speech presentation rate. This is inconsistent with previous studies that have investigated rate preferences among older adults, and could reflect the different synthesized speech options employed in this study. Implications of these findings for the improvement of text-to-speech products and the practice of AAC are discussed, along with suggestions for further research.

Moebius syndrome: measures of observer intelligibility with versus without visual cues in bilateral facial paralysis.

OBJECTIVE: This study investigated observers' intelligibility for the spoken output of an individual with Moebius syndrome (MoS) with and without visual cues. DESIGN: An audiovisual recording of the speaker's output was obtained for 50 Speech Intelligibility in Noise sentences consisting of 25 high predictability and 25 low predictability sentences. Stimuli were presented to observers under two conditions: audiovisual and audio only. Data were analyzed using a multivariate repeated measures model. OBSERVERS: Twenty students and faculty affiliated with the Department of Speech Pathology and Audiology at the University of Nevada, Reno. RESULTS: ANOVA mixed design revealed that intelligibility for the audio condition only was significantly greater than intelligibility for the audiovisual condition; and accuracy for high predictability sentences was significantly greater than accuracy for low predictability sentences. CONCLUSIONS: The compensatory substitutional placements for phonemes produced by MoS speakers may detract from the intelligibility of speech. This is similar to the McGurk-MacDonald effect, whereby an illusory auditory signal is perceived when visual information from lip movements does not match the auditory information from speech. It also suggests that observers use contextual clues, more than the acoustic signal alone, to arrive at the accurate recognition of the message of the speakers with MoS. Therefore, speakers with MoS should be counseled in the top-down approach of auditory closure. When the speech signal is degraded, predictable messages are more easily understood than unpredictable ones. It is also important to confirm the speaking partner's understanding of the topic before proceeding.

Effects of alternative communication on the communicative effectiveness of an individual with a progressive language disorder.

This study was designed to investigate the effects of two different modes of communication on the communicative output of an individual who is no longer able to communicate verbally, presenting with a primary progressive aphasia and apraxia of speech. The two treatment approaches included training the patient with a text-to-speech alternative communication device and with American sign language. An alternating treatment design was used to compare two communicative approaches (an alternative communication device and American sign language) on the subject's communicative effectiveness. Communicative effectiveness was measured in terms of number of words, correct information units and percentage correct information units, using a protocol that was adapted to quantify the output generated by the alternative communication device and American sign language. Increases across all three measures resulted for both the alternative communication device and American sign language. The clinical implications are explored, and the results add to existing studies regarding treatment possibilities using alternative communication for individuals who present with a progressive speech and language disorder, without concomitant cognitive deficits.