The relationship of speech perception and speech production: It's complicated.

A widely held belief is that speech perception and speech production are tightly linked, with each modality available to help with learning in the other modality. This positive relationship is often summarized as perception and production being "two sides of the same coin." There are, indeed, many situations that have shown this mutually supportive relationship.

Examining the Relationship Between Multiple Tests of Receptive Vocabulary.

Purpose: Numerous tasks have been developed to measure receptive vocabulary, many of which were designed to be administered in person with a trained researcher or clinician. The purpose of the current study is to compare a common, in-person test of vocabulary with other vocabulary assessments that can be self-administered.

Method: Fifty-three participants completed the Peabody Picture Vocabulary Test (PPVT) via online video call to mimic in-person administration, as well as four additional fully automated, self-administered measures of receptive vocabulary.

Passive exposure to task-relevant stimuli enhances categorization learning.

Learning to perform a perceptual decision task is generally achieved through sessions of effortful practice with feedback. Here, we investigated how passive exposure to task-relevant stimuli, which is relatively effortless and does not require feedback, influences active learning. First, we trained mice in a sound-categorization task with various schedules combining passive exposure and active training.

Selectivity to acoustic features of human speech in the auditory cortex of the mouse.

A better understanding of the neural mechanisms of speech processing can have a major impact in the development of strategies for language learning and in addressing disorders that affect speech comprehension. Technical limitations in research with human subjects hinder a comprehensive exploration of these processes, making animal models essential for advancing the characterization of how neural circuits make speech perception possible. Here, we investigated the mouse as a model organism for studying speech processing and explored whether distinct regions of the mouse auditory cortex are sensitive to specific acoustic features of speech.

Selectivity to acoustic features of human speech in the auditory cortex of the mouse.

A better understanding of the neural mechanisms of speech processing can have a major impact in the development of strategies for language learning and in addressing disorders that affect speech comprehension. Technical limitations in research with human subjects hinder a comprehensive exploration of these processes, making animal models essential for advancing the characterization of how neural circuits make speech perception possible. Here, we investigated the mouse as a model organism for studying speech processing and explored whether distinct regions of the mouse auditory cortex are sensitive to specific acoustic features of speech.

Passive exposure to task-relevant stimuli enhances categorization learning.

Learning to perform a perceptual decision task is generally achieved through sessions of effortful practice with feedback. Here, we investigated how passive exposure to task-relevant stimuli, which is relatively effortless and does not require feedback, influences active learning. First, we trained mice in a sound-categorization task with various schedules combining passive exposure and active training.

The Effects of Acoustic and Semantic Enhancements on Perception of Native and Non-Native Speech.

Previous research has shown that native listeners benefit from clearly produced speech, as well as from predictable semantic context when these enhancements are delivered in native speech. However, it is unclear whether native listeners benefit from acoustic and semantic enhancements differently when listening to other varieties of speech, including non-native speech. The current study examines to what extent native English listeners benefit from acoustic and semantic cues present in native and non-native English speech.

Intelligibility as a measure of speech perception: Current approaches, challenges, and recommendations.

Intelligibility measures, which assess the number of words or phonemes a listener correctly transcribes or repeats, are commonly used metrics for speech perception research. While these measures have many benefits for researchers, they also come with a number of limitations. By pointing out the strengths and limitations of this approach, including how it fails to capture aspects of perception such as listening effort, this article argues that the role of intelligibility measures must be reconsidered in fields such as linguistics, communication disorders, and psychology.

The nature of non-native speech sound representations.

Most current theories and models of second language speech perception are grounded in the notion that learners acquire speech sound categories in their target language. In this paper, this classic idea in speech perception is revisited, given that clear evidence for formation of such categories is lacking in previous research. To understand the debate on the nature of speech sound representations in a second language, an operational definition of "category" is presented, and the issues of categorical perception and current theories of second language learning are reviewed.

Non-native English listeners' adaptation to native English speakers.

Listeners often have difficulty understanding unfamiliar speech (e.g., non-native speech), but they are able to adapt to or improve their ability to understand unfamiliar speech.

Just give it time: Differential effects of disruption and delay on perceptual learning.

Speech perception and production are critical skills when acquiring a new language. However, the nature of the relationship between these two processes is unclear, particularly for non-native speech sound contrasts. Although it has been assumed that perception and production are supportive, recent evidence has demonstrated that, under some circumstances, production can disrupt perceptual learning.

Perceptual consequences of native and non-native clear speech.

Native talkers are able to enhance acoustic characteristics of their speech in a speaking style known as "clear speech," which is better understood by listeners than "plain speech." However, despite substantial research in the area of clear speech, it is less clear whether non-native talkers of various proficiency levels are able to adopt a clear speaking style and if so, whether this style has perceptual benefits for native listeners. In the present study, native English listeners evaluated plain and clear speech produced by three groups: native English talkers, non-native talkers with lower proficiency, and non-native talkers with higher proficiency.

Effects of Spectral Envelope and Fundamental Frequency Shifts on the Perception of Foreign-Accented Speech.

To investigate the role of spectral pattern information in the perception of foreign-accented speech, we measured the effects of spectral shifts on judgments of talker discrimination, perceived naturalness, and intelligibility when listening to Mandarin-accented English and native-accented English sentences. In separate conditions, the spectral envelope and fundamental frequency (F0) contours were shifted up or down in three steps using coordinated scale factors (multiples of 8% and 30%, respectively). Experiment 1 showed that listeners perceive spectrally shifted sentences as coming from a different talker for both native-accented and foreign-accented speech.

Lexical Diversity, Lexical Sophistication, and Predictability for Speech in Multiple Listening Conditions.

When talkers anticipate that a listener may have difficulty understanding their speech, they adopt a speaking style typically described as "clear speech." This speaking style includes a variety of acoustic modifications and has perceptual benefits for listeners. In the present study, we examine whether clear speaking styles also include modulation of lexical items selected and produced during naturalistic conversations.

Semantic predictability and adaptation to nonnative speech.

Listeners improve their ability to understand nonnative speech through exposure. The present study examines the role of semantic predictability during adaptation. Listeners were trained on high-predictability, low-predictability, or semantically anomalous sentences.

Rapid adaptation to non-native speech is impaired in cochlear implant users.

To examine difficulties experienced by cochlear implant (CI) users when perceiving non-native speech, intelligibility of non-native speech was compared in conditions with single and multiple alternating talkers. Compared to listeners with normal hearing, no rapid talker-dependent adaptation was observed and performance was approximately 40% lower for CI users following increased exposure in both talker conditions. Results suggest that lower performance for CI users may stem from combined effects of limited spectral resolution, which diminishes perceptible differences across accents, and limited access to talker-specific acoustic features of speech, which reduces the ability to adapt to non-native speech in a talker-dependent manner.

Investigating a bias for cue preservation in loanword adaptation.

Loanword adaptation exhibits a bias favoring sound cue preservation, possibly due to a conservative caution against deleting cues of unsure expendability in a foreign language. This study tests whether listeners are biased to preserve an acoustically ambiguous sound cue in a nonce word framed as originating from a foreign language. Results show the opposite: Listeners are less likely to transcribe an ambiguous sound cue as a phonological segment when the word containing it is framed as a loanword.

The maintenance of clear speech in naturalistic conversations.

Clear speech is a style that speakers adopt when talking with listeners whom these speakers anticipate may have a problem understanding speech. This study examines whether native English speakers use clear speech in conversations with non-native English speakers when native speakers are not explicitly asked to use clear speech (i.e.

Perceptual Consequences of Variability in Native and Non-Native Speech.

Background/aims: Native speakers often have a difficult time understanding non-native speech, and this challenge is frequently attributed to a more variable signal. While theories and models of general speech perception are grounded in issues of variability, they rarely consider non-native speech. Here, we ask how a specific type of variability (speaking rate) impacts two measures of perception for both native and non-native speech.

Interactions between speech perception and production during learning of novel phonemic categories.

A successful language learner must be able to perceive and produce novel sounds in their second language. However, the relationship between learning in perception and production is unclear. Some studies show correlations between the two modalities; however, other studies have not shown such correlations.

Not just a function of function words: Distal speech rate influences perception of prosodically weak syllables.

Listeners resolve ambiguities in speech perception using multiple sources, including non-local or distal speech rate (i.e., the speech rate of material surrounding a particular region).

Coping with adversity: Individual differences in the perception of noisy and accented speech.

During speech communication, both environmental noise and nonnative accents can create adverse conditions for the listener. Individuals recruit additional cognitive, linguistic, and/or perceptual resources when faced with such challenges. Furthermore, listeners vary in their ability to understand speech in adverse conditions.

Revisiting Neil Armstrongs Moon-Landing Quote: Implications for Speech Perception, Function Word Reduction, and Acoustic Ambiguity.

Neil Armstrong insisted that his quote upon landing on the moon was misheard, and that he had said one small step for a man, instead of one small step for man. What he said is unclear in part because function words like a can be reduced and spectrally indistinguishable from the preceding context. Therefore, their presence can be ambiguous, and they may disappear perceptually depending on the rate of surrounding speech.

Dimensions of similarity in the mental lexicon.

During language production planning, multiple candidate representations are implicitly activated prior to articulation. Lexical representations that are phonologically related to the target (phonological neighbors) are known to influence phonetic properties of the target word. However, the question of which dimensions of phonological similarity contribute to such lexical-phonetic effects remains unanswered.

Speaking rate consistency in native and non-native speakers of English.

Non-native speech differs from native speech in multiple ways. Previous research has described segmental and suprasegmental differences between native and non-native speech in terms of group averages. For example, average speaking rate for non-natives is slower than for natives.