Tactile communication of speech: II. Comparison of two spectral displays in a vowel discrimination task.
Vowel discrimination experiments were performed comparing two tactile, Optacon-based, spectral displays: a frequency-amplitude (FA) display and a time-swept (TS) display. The set of vowel pairs tested consisted of all pairs from the set of ten American nondipthongized vowels. One set of materials consisted of natural /b/-V-/t/'s (with each vowel represented by 12 utterances generated by four speakers producing each vowel three times). A second set consisted of synthetic vowels (with each vowel represented by a single waveform). On the average, th score obtained with the second set of materials was substantially better than with the first (92% vs 79%); the score obtained with the TS display was slightly better than with the FA display (87% vs 83%); the feature best differentiated was tenseness, followed by the features high and low, then by round and back, and finally by retroflexion; and the correlation between discrimination performance and the physical parameters duration, amplitude, F1, and F2/F1 (taken singly) was relatively weak. In general, the results of this study, together with those of other studies previously reported, suggest that the two displays studied are far from optimum.
D003626:Data Display; D005246:Feedback; D006801:Humans; D008722:Methods; D010700:Phonetics; D013067:Speech Perception; D014110:Touch