Phonetic segment switching based on differential-encoding of the vocal tract resonances

Previous work has shown that speech segments can be encoded by specifying relative acoustic events along a time axis that consist of directional changes of the vocal tract resonance frequencies called resonance deflection patterns (RDPs) [JASA, 146(4), 2522–2528]. These events are transformed via acoustic sensitivity functions, into time-varying modulations of the vocal tract shape. RDPs specifying /b, p/, /d, t/, and /g, k/, for example, would typically be coded as [−1 −1 −1], [−1 1 1], and [−1 1 −1], respectively, where the vectors indicate, from left to right, the targeted directional shift of the first, second, and third resonances of the vocal tract. The specific aim of this study was to determine if listeners' recognition of speech synthesized in the RDP paradigm aligns with the RDP settings. That is, if RDPs are conceived as a bank of switches, can word recognition be guided by changes in the pattern of switch settings. A synthesized version of “abracadabra” was used as the baseline word. Variations were generated by systematically changing the RDPs for consonants in the initial “abra” and in the final “dabra” to generate new targets such as “aglacabadra.” Listener responses to these variations will be reported.