Syllable is a synchronization mechanism that makes human speech possible

Abstract

Speech is a highly skilled motor activity that shares a core problem with other motor skills: how to reduce the massive degrees of freedom (DOF) to the extent that the central nervous control and learning of complex motor movements become possible. It is hypothesized in this paper that a key solution to the DOF problem is to eliminate most of the temporal degrees of freedom by synchronizing concurrent movements, and that this is done in speech through the syllablea mechanism that synchronizes consonantal, vocalic and laryngeal gestures. Under this hypothesis, gestures are articulatory movements toward underlying targets; the onsets and offsets of the gestures are synchronized at the syllable edges, although more so at syllable onset than at the offset; and the realization of the synchronization is facilitated by sensorimotor feedback, especially tactile feedback, during consonant closures. This synchronization theory of the syllable also offers a comprehensive account of coarticulation, as it explicates how various coarticulation-related phenomena, including coarticulation resistance, locus, locus equation, diphone etc., are byproducts of syllable formation. It also provides a theoretical basis for understanding how suprasegmental events such as tone, intonation, phonation, etc. are aligned to segmental events in speech. It may also have implications for understanding vocal learning, speech disorders and motor control in general.Xu, Y. (2020) Syllable Is a synchronization mechanism that makes human speech possible. PsyArXiv doi:10.31234/osf.io/9v4hr.

Segmental Alignment of English Syllables with Singleton and Cluster Onsets

“…The results showed that a neural network classifier can detect categorical information in the acoustic signal around the same time for the onset C/CL and the nucleus vowel. Therefore, the results support the notion of synchronisation -that the start of the vowel is synchronised with the onset consonant [9], for both singleton and cluster onsets [2]. Most importantly, contrary to the prediction of the c-center hypothesis, the results do not show that the cluster onset precedes the vowel onset.…”

“…Evidence for co-production between syllable initial segments has been shown from the very early days of phonetic research, e.g., the observation of lip rounding at the beginning of /ku/ [4], tongue rising at the start of /bi/ [5], and simultaneous articulation between onset cluster [6] [7]. This has led to models that predict CV synchrony at the syllable onset, including the articulatory syllable model [2], the Task Dynamics (TD)/Articulatory Phonology (AP) frameworks [8] and the synchronisation model of the syllable [9]. The strongest claim among these models is that the co-onset happens between the vowel and the very first consonant in an onset cluster, and the syllable is the domain of coarticulation [2].…”

Consonantal F0 perturbation in American English involves multiple mechanisms

“…The alignment method used in the present study is based on the assumption that underlying pitch targets associated with a syllable is synchronized with the entire syllable rather than with only the syllable rhyme (Xu and Liu, 2006;Xu, 2020). Based on this assumption, while voice breaks may mask continuous F0 contours, they do not interrupt the underlying laryngeal movements that produce them.…”

“…It has been shown that the F0 contour of a syllable in English is a movement toward an underlying pitch target associated with lexical stress as well as other concurrent functions (Fry, 1958;Liu et al, 2013;Xu and Xu, 2005). It is further shown that such target approximation movement is synchronized with the syllable in English (Prom-on, Xu and Thipakorn, 2009;Xu and Prom-on, 2014;Xu and Xu, 2005), just like in Mandarin (Xu, 1998(Xu, , 1999, i.e., starting from the syllable onset and ending by syllable offset (Xu and Wang, 2001;Xu, 2020).…”

The PENTA Model: Concepts, Use, and Implications

“…The other hypothesized aspect of the pitch production mechanism is the syllabic synchronization of target approximation movements. That is, laryngeal and supralaryngeal movements are synchronized with re spect to the syllable (Xu 2020;Liu 2006, 2012). This assumption is motivated not only by observations like those shown in figure 11.2, but also by findings that the motor system is able to coordinate multiple movements at a fast speed only through full synchrony (Kelso 1984;Kelso, Southard, and Goodman 1979;Mechsner et al 2001).…”