Clear Communication Group

Our Research

Clear Speech | Interpreter Intelligibility | EIPA-CS

Clear Speech

Clear speech refers to a speaking style that is significantly more intelligible than conversational speech for a variety of listeners and backgrounds such as noise and reverberation. Although typically spoken more slowly than conversational speech, talkers can produce clear speech at normal rates with training. By examining the acoustics of this form of clear speech (clear/normal speech) and the extent to which it preserves the widespread intelligibility benefits of clear (clear/slow) speech, our goal is to identify acoustic characteristics of highly intelligible speech and to determine the extent to which those characteristics differ for various populations and listening situations. Such information should not only suggest potential signal processing techniques for hearing aids but also increase our basic understanding of speech reception.

Selected Publication(s):

Jean C. Krause and Louis D. Braida (2009). “Evaluating the role of spectral and envelope characteristics in the intelligibility advantage of clear speech,” J. Acoust. Soc. Am., Vol. 125, No. 5, pp. 3346-3357.

Jean C. Krause and Louis D. Braida (2004). “Acoustic properties of naturally produced clear speech at normal speaking rates,” J. Acoust. Soc. Am., Vol. 115, No. 1, pp. 362-378.

Jean C. Krause and Louis D. Braida (2002). “Investigating alternative forms of clear speech: The effects of speaking rate and speaking mode on intelligibility,” J. Acoust. Soc. Am., Vol. 112, No. 5, pp. 2165-2172.

TerpIntell Picture

Interpreter Intelligibility

Although it is common practice for deaf individuals to use interpreters as a means of accessing spoken information, little is known about interpreter intelligibility (amount of message correctly transmitted to deaf individuals who use interpreters) or the factors that govern interpreter intelligibility. This information is essential for characterizing the level of communication access afforded to deaf individuals by interpreters and could be of particularly serious consequence for deaf children still in the process of acquiring language. Our work in this area is aimed at quantifying relationships between interpreter intelligibility and specific physical characteristics of the visual signal produced by interpreters. While many such relationships have been specified for speech, the factors that govern the intelligibility of American Sign Language (ASL) and other English-based visual communication methods are largely unknown. In this project, we begin to examine these relationships for three English-based visual communication modes: Conceptually Accurate Signed English (CASE), Signing Exact English (SEE), and Cued Speech (CS). Specifically, we explore how the accuracy (percent of the spoken message correctly produced) and lag time (interval between spoken and visual message) of the visual message as well as the rate at which it is presented affect an interpreter's (i.e. transliterator's) intelligibility. Results will establish characteristics of highly intelligible transliterators, an important first step toward long-term goals aimed at improving: 1) transliterator training and services, 2) communication access for deaf individuals who use transliterators, and 3) scientific understanding of intelligibility in the visual modality and perception across all modes of sensory communication.

Selected Publication(s):

Jean C. Krause and Katherine A. Lopez (2017). “Cued Speech Transliteration: Effects of Accuracy and Lag Time on Message Intelligibility,” J. Deaf Stud. Deaf Educ.

Jean C. Krause and Morgan P. Tessler (2016). “Cued Speech transliteration: Effects of speaking rate and lag time on production accuracy,” J. Deaf Stud. Deaf Educ. Vol. 21, No. 4, pp. 373-382.

Jean C. Krause, Katherine A. Pelley-Lopez, and Morgan P. Tessler (2011). “A method for transcribing the manual components of Cued Speech,” Speech Comm., Vol. 53, No. 3, pp. 379–389.

Jean C. Krause and Abby N. Bennett (2010). "The role of speechreadability in the intelligibility of visual speech signals produced by Cued Speech transliterators," Cancun, Mexico: J. Acoust. Soc. Am., Vol. 128, No. 4, Pt. 2, pg. 2318 (poster).

Educational Interpreter Performance Assessment for Cued Speech transliterators (EIPA-CS)

EIPA-CS Picture The Educational Interpreter Performance Assessment (EIPA) represents the first large-scale attempt to evaluate competencies of educational interpreters and to provide them with diagnostic feedback for improving their skills. From its inception, it covered a wide variety of educational interpreting situations, offering tests at two grade levels (elementary and secondary) for three communication options (American Sign Language, Pidgin Signed English, and Signed Exact English). In this project, a pilot EIPA test was designed and developed for the Cued Speech communication option. The tool received endorsement from the National Cued Speech Association (see Press Release - 6/25/08) and was adopted by the EIPA Diagnostic Center at Boys Town National Research Hospital (BTNRH) in 2010, expanding the applicability of the EIPA to Cued Speech transliterators. For more information about the EIPA, and EIPA-CS, please visit

Selected Publication(s):

Krause, J.C., Schick, B., Kegl, J.A. (2010). “A version of the Educational Interpreter Performance Assessment for Cued Speech transliterators: Prospects and significance.” In C.J. LaSasso, K.L. Crain, J. Leybaert (Eds.), Cued Speech and Cued Language Development of Deaf Students, (pp. 531-551). San Diego, CA: Plural Publishing, Inc.

Jean C. Krause, Judy A. Kegl, and Brenda Schick (2008). “Toward Extending the Educational Interpreter Performance Assessment to Cued Speech,” J. Deaf Stud. Deaf Educ., Vol. 13, No. 3, pp. 432-450.