ERIC Number: EJ1029474
Record Type: Journal
Publication Date: 2014-Feb
Abstractor: As Provided
Reference Count: N/A
Large-Corpus Phoneme and Word Recognition and the Generality of Lexical Context in CVC Word Perception
Gelfand, Jessica T.; Christie, Robert E.; Gelfand, Stanley A.
Journal of Speech, Language, and Hearing Research, v57 n1 p297-307 Feb 2014
Purpose: Speech recognition may be analyzed in terms of recognition probabilities for perceptual wholes (e.g., words) and parts (e.g., phonemes), where j or the j-factor reveals the number of independent perceptual units required for recognition of the whole (Boothroyd, 1968b; Boothroyd & Nittrouer, 1988; Nittrouer & Boothroyd, 1990). For consonant-vowel-consonant (CVC) nonsense syllables, j ~ 3 because all 3 phonemes are needed to identify the syllable, but j ~ 2.5 for real-word CVCs (revealing ~2.5 independent perceptual units) because higher level contributions such as lexical knowledge enable word recognition even if less than 3 phonemes are accurately received. These findings were almost exclusively determined with the 120-word corpus of the isophonemic word lists (Boothroyd, 1968a; Boothroyd & Nittrouer, 1988), presented one word at a time. It is therefore possible that its generality or applicability may be limited. This study thus determined j by using a much larger and less restricted corpus of real-word CVCs presented in 3-word groups as well as whether j is influenced by test size. Method: The j-factor for real-word CVCs was derived from the recognition performance of 223 individuals with a broad range of hearing sensitivity by using the Tri-Word Test (Gelfand, 1998), which involves 50 three-word presentations and a corpus of 450 words. The influence of test size was determined from a subsample of 96 participants with separate scores for the first 10, 20, and 25 (and all 50) presentation sets of the full test. Results: The mean value of j was 2.48 with a 95% confidence interval of 2.44-2.53, which is in good agreement with values obtained with isophonemic word lists, although its value varies among individuals. A significant correlation was found between percent-correct scores and j" but it was small and accounted for only 12.4% of the variance in j for phoneme scores =60%. Mean j-factors for the 10-, 20-, 25-, and 50-set test sizes were between 2.49 and 2.53 and were not significantly different from one another. Conclusions: The j-factor based on a 450-word corpus and tri-word testing confirms and expands on findings from single-word presentations of isophonemic lists and a 120-word corpus. This enhances the generality (external validity) of the notions that j ~ 2.5 for real-word CVCs, and lexical knowledge enables CVC word recognition based on ~2.5 independent perceptual units. The robust nature of isophonemic word test outcomes is confirmed by close agreement with those provided by the high-reliability Tri-Word Test. Percent-correct performance was correlated with j but appeared to account for less than 13% of j-factor variance for most scores likely to be encountered in practice. Variability in the size of j suggests individual differences in the ability to take advantage of lexical knowledge in word recognition. The j-factor may be useful to inform rehabilitation needs, intervention content, and outcome assessment, as well as for other clinical applications.
Descriptors: Phonemes, Word Recognition, Vowels, Syllables, Test Length, Word Lists, Correlation, Computation, Statistical Analysis, Scores
American Speech-Language-Hearing Association (ASHA). 10801 Rockville Pike, Rockville, MD 20852. Tel: 800-638-8255; Fax: 301-571-0457; e-mail: email@example.com; Web site: http://jslhr.asha.org
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Authoring Institution: N/A