First Advisor

John Tetnowski

Term of Graduation

Summer 1998

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Speech: Speech and Hearing Sciences


Speech Communication




Diastema (Teeth), Articulation disorders



Physical Description

1 online resource (69 pages)


An important morphological-marker and one of the most frequently occurring speech sounds in English, the /s/ phoneme is also one of the sounds most often in need of remediation. Often, air emission during /s/ production, a particularly stubborn, often residual production error, is not remediated through traditional treatment methods, and yet the negative effect /s/ distortions have on listeners has been well-documented.

The subject of this investigation was a forty-eightyear-old male who received treatment for a lateralized /s/ during grade-school. It was hypothesized that his exerting high anterior pressure to prevent air from escaping from a diastema between his two maxillary incisors during /s/ production created lateral openings through which air was escaping. McGlone and Proffit (1973, 1974) found that subjects who had lateralized /s/ exerted a great deal of pressure on the anterior region of the palate. Closing the diastema might reduce anterior pressure and thus provide a means toward improved /s/ production.

Before having his diastema closed, the subject responded to items on the Photo Articulation test and the Dworkin-Culatta Oral Mechanism Examination. To establish a baseline of correct .Isl productions,. a digital audio tape (DAT) recording was made of the subject reading words and sentences taken from Eugene T. McDonald's DEEP test of Articulation and the Rainbow passage. The subject's diastema was then closed using a common dental practice. Subsequent recordings were made four days after and then again one month after the procedure. Three graduate students rated the tapes for presence or absence of air emission during /s/ productions. A phonological context evaluation was so performed as well as a spectrographic analysis of selected productions.

While the data in this study do not support that closing the diastema remediated the subject's lateral /s/, the phonological context data do support that complex speech demands negatively impacted the subject's Is/ production, and that his best performance was in the context of speech sounds that do not require precise articulatory movement or breath control. A spectrographic evaluation revealed higher levels of spectral noise in the high frequencies when air emission was present.


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