Pause Postures: The relationship between articulation and cognitive processes during pauses.

Studies examining articulatory characteristics of pauses have identified language-specific postures of the vocal tract in inter-utterance pauses and different articulatory patterns in grammatical and non-grammatical pauses. Pause postures-specific articulatory movements that occur during pauses at strong prosodic boundaries-have been identified for Greek and German. However, the cognitive function of these articulations has not been examined so far. We start addressing this question by investigating the effect of 1) utterance type and 2) planning on pause posture occurrence and properties in American English. We first examine whether pause postures exist in American English. In an electromagnetic articulometry study, seven participants produced sentences varying in linguistic structure (stress, boundary, sentence type). To determine the presence of pause postures, as well as to lay the groundwork for their future automatic annotation and detection, a Support Vector Machine Classifier was built to identify pause postures. Results show that pause postures exist for all speakers in this study but that the frequency of occurrence is speaker dependent. Across participants, we find that there is a stable relationship between the pause posture and other events (boundary tones and vowels) at prosodic boundaries, parallel to previous work in Greek. We find that the occurrence of pause postures is not systematically related to utterance type. Lastly, pause postures increase in frequency and duration as utterance length increases, suggesting that pause postures are at least partially related to speech planning processes

A potential role for reinforcement learning in speech production

AbstractReinforcement learning, the ability to change motor behavior based on external reward, has been suggested to play a critical role in early stages of speech motor development and is widely used in clinical rehabilitation for speech motor disorders. However, no current evidence exists that demonstrates the capability of reinforcement to drive changes in human speech behavior. Speech provides a unique test of the universality of reinforcement learning across motor domains: speech is a complex, high-dimensional motor task whose goals do not specify a task to be performed in the environment but ultimately must be self-generated by each speaker such that they are understood by those around them. Across four experiments, we examine whether reinforcement learning alone is sufficient to drive changes in speech behavior and parametrically test two features known to affect reinforcement learning in reaching: how informative the reinforcement signal is as well as the availability of sensory feedback about the outcomes of one’s motor behavior. We show that learning does occur and is more likely when participants receive auditory feedback that gives an implicit target for production, even though they do not explicitly imitate that target. Contrary to results from upper limb control, masking feedback about movement outcomes has no effect on speech learning. Together, our results suggest a potential role for reinforcement learning in speech but that it likely operates differently than in other motor domains.</jats:p

Dynamical account of how /b, d, g/ differ from /p, t, k/ in Spanish: Evidence from labials

AbstractThis study examines articulatory lenition of intervocalic stops in Spanish and tests the theories that 1) /b, d, g/ have an intended target for closure equal to that of /p, t, k/ and 2) spirantization of /b, d, g/ is caused by undershoot due to their short duration phrase medially. Consistent with past acoustic studies, subjects produce /b/ with incomplete closure phrase medially and complete closure phrase initially. Additionally, /b/ is shorter than /p/ phrase medially though not initially. For /b/, though not for /p/, there is a correlation between constriction degree and duration, consistent with the theory of dynamical undershoot. The results from the study are accurately modeled with a virtual target for /b/ slightly beyond the point of articulator contact. Such a target results in full closure at long durations (such as found phrase initially) and incomplete closure at shorter durations. Based on this evidence, it is proposed that /b, d, g/ differ from /p, t, k/ in three ways: they are shorter, lack a devoicing gesture, and have a target closer to – but still beyond – the point of articulator contact.</jats:p

A Potential Role for Reinforcement Learning in Speech Production

Abstract Reinforcement learning, the ability to change motor behavior based on external reward, has been suggested to play a critical role in early stages of speech motor development and is widely used in clinical rehabilitation for speech motor disorders. However, no current evidence exists that demonstrates the capability of reinforcement to drive changes in human speech behavior. Speech provides a unique test of the universality of reinforcement learning across motor domains: Speech is a complex, high-dimensional motor task whose goals do not specify a task to be performed in the environment but ultimately must be self-generated by each speaker such that they are understood by those around them. Across four experiments, we examine whether reinforcement learning alone is sufficient to drive changes in speech behavior and parametrically test two features known to affect reinforcement learning in reaching: how informative the reinforcement signal is as well as the availability of sensory feedback about the outcomes of one's motor behavior. We show that learning does occur and is more likely when participants receive auditory feedback that gives an implicit target for production, although they do not explicitly imitate that target. Contrary to results from upper limb control, masking feedback about movement outcomes has no effect on speech learning. Together, our results suggest a potential role for reinforcement learning in speech but that it likely operates differently than in other motor domains.</jats:p