Learners' ability to recognize linguistic contrasts in American Sign Language (ASL) was investigated using a paired-comparison discrimination task. Minimal pairs containing contrasts in five linguistic categories (i.e., the formational parameters of movement, handshape, orientation, and location in ASL phonology, and a category comprised of contrasts in complex morphology) were presented in sentence contexts to a sample of 127 hearing learners at beginning and intermediate levels of proficiency and 10 Deaf native signers. Participants' responses were analyzed to determine the relative difficulty of the linguistic categories and the effect of proficiency level on performance. The results indicated that movement contrasts were the most difficult and location contrasts the easiest, with the other categories of stimuli of intermediate difficulty. These findings have implications for language learning in situations in which the first language is a spoken language and the second language (L2) is a signed language. In such situations, the construct of language transfer does not apply to the acquisition of L2 phonology because of fundamental differences between the phonological systems of signed and spoken languages, which are associated with differences between the modalities of speech and sign.The authors are grateful to Tom Weymann and Sarah Schley for their assistance in conducting the data analysis, Gaurav Mathur and the anonymous reviewers for their thoughtful comments and helpful suggestions, and Joe Hamilton, Jenamarie Bacot, and Jon Lejeune for helping to develop and record the stimuli.

American Sign Language (ASL) is one of the most commonly taught languages in North America. Yet, few assessment instruments for ASL proficiency have been developed, none of which have adequately demonstrated validity. We propose that the American Sign Language Discrimination Test (ASL-DT), a recently developed measure of learners’ ability to discriminate phonological and morphophonological contrasts in ASL, provides an objective overall measure of ASL proficiency. In this study, the ASL-DT was administered to 194 participants at beginning, intermediate, and high levels of ASL proficiency, a subset of which ( N = 57) also was administered the Sign Language Proficiency Interview (SLPI), a widely used subjective proficiency measure. Using Rasch analysis to model ASL-DT item difficulty and person ability, we tested the ability of the ASL-DT Rasch measure to detect participant proficiency group mean differences and compared its discriminant performance to the SLPI ratings for classifying individuals into their pre-assigned proficiency groups using resource operating characteristic statistics. The ASL-DT Rasch measure outperformed the SLPI ratings, indicating that the ASL-DT may provide a valid objective measure of overall ASL proficiency. As such, the ASL-DT Rasch measure may provide a useful complement to measures such as the SLPI in comprehensive sign language assessment programs.

The ability to discriminate changes in the length of vowels and tonal complexes (filled intervals) and in the duration of closure in stop consonants and gaps in tonal complexes (unfilled intervals) was studied in three normally hearing and seven severely hearing-impaired listeners. The speech stimuli consisted of the vowels (i, I, u, U, a, A) and the consonants (p, t, k), and the tonal complexes consisted of digitally generated sinusoids at 0.5, 1, and 2 kHz. The signals were presented at conversational levels for each listener group, and a 3IFC adaptive procedure was used to estimate difference limens (DLs). The DLs for speech were similar to those for tonal complex stimuli in both the filled and unfilled conditions. Both normally and impaired-hearing listeners demonstrated greater acuity for changes in the duration of filled than unfilled intervals. Mean thresholds for filled intervals obtained from normally hearing listeners were smaller than those obtained from hearing-impaired listeners. For unfilled intervals, however, the difference between listener groups was not significant. A few hearing-impaired listeners demonstrated temporal acuity comparable to that of normally hearing listeners for several listening conditions. Implications of these results are discussed with regard to speech perception in normally and impaired-hearing individuals.

The purpose of this study was to investigate the utility of a measure of communication efficacy, one that explicitly encompasses features of both speech and language. Toward this end the construct of comprehensibility, which has been used in the field of second-language acquisition, was adapted. Comprehensibility, operationally defined as the extent to which a listener understands utterances produced by a speaker in a communication context, was studied in relation to various dimensions of communication efficacy. Four observers evaluated the comprehensibility of utterances produced by 41 deaf young adults, using a nine-point rating scale. The reliability of the comprehensibility ratings was determined, and the ratings were studied in relation to independent assessments of the subjects’ speech intelligibility, English language proficiency, speech recognition, reading comprehension, and hearing loss. The results of this investigation indicate that comprehensibility can be evaluated reliably and that comprehensibility is associated with both speech intelligibility and language proficiency. The implications of these findings for the clinical assessment of speech and language are discussed.

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