The specific-word frequency effect in speech production: Evidence from Spanish and French

The role of word frequency in lexical access during the production of homophones remains unresolved. In the current study, we address whether specific-word (the frequency of occurrence of the word “nun”) or homophone frequency (the summed frequency of words with the pronunciation /nΛn/) determines the production latencies of homophones. In Experiments 1a, 2a, and 3a, participants named pictures of high-frequency (e.g., “banco”–a bank: financial institution) and low-frequency (e.g., “banco”–park bench) Spanish (Experiments 1a and 2a) or French (Experiment 3a) homophones and control pictures of nonhomophone words matched in frequency with each of the two uses of the homophones. The naming latencies for low-frequency homophones were longer than those for high-frequency homophones. Furthermore, the naming latencies for homophones were indistinguishable from those for nonhomophone controls matched in specific-word frequency. In Experiments 1b, 2b, and 3b, the participants performed either object decision or picture–word matching tasks with the stimuli used in the corresponding Experiments 1a, 2a, and 3a. There were no reliable differences between high- and low-frequency homophones. The findings support the hypothesis that specific-word and not homophone frequency determines lexical access in speech production.     

The representation of homophones: evidence from the distractor-frequency effect

Current models of word production offer different accounts of the representation of homophones in the lexicon. The investigation of how the homophone status of a word affects lexical access can be used to test theories of lexical processing. In this study, homophones appeared as word distractors superimposed on pictures that participants named orally. The authors varied distractor frequency, a variable that has been shown to modulate the interference that distractors produce on picture naming. The results of 3 experiments converged in showing that words interfered in proportion to their individual frequency in the language, even if they have high-frequency homophone mates. This effect of specific-word frequency is compatible with models that assume (a) distinct lexical representations for the individual homophones and (b) that access to such representations is modulated by frequency. The authors discuss the extent to which current models of word production satisfy these constraints.     

The effect of sublexical and lexical frequency on speech production: An fMRI investigation

There is no consensus regarding the fundamental phonetic units that underlie speech production. There is, however, general agreement that the frequency of occurrence of these units is a significant factor. Investigators often use the effects of manipulating frequency to support the importance of particular units. Studies of pseudoword production have been used to show the importance of sublexical units, such as initial syllables, phonemes, and biphones. However, it is not clear that these units play the same role when the production of pseudowords is compared to the production of real words. In this study, participants overtly repeated real and pseudowords that were similar for length, complexity, and initial syllable frequency while undergoing functional magnetic resonance imaging. Compared to real words, production of pseudowords produced greater activation in much of the speech production network, including bilateral inferior frontal cortex, precentral gyri and supplementary motor areas and left superior temporal cortex and anterior insula. Only middle right frontal gyrus showed greater activation for real words than for pseudowords. Compared to a no-speech control condition, production of pseudowords or real words resulted in activation of all of the areas shown to comprise the speech production network. Our data, in conjunction with previous studies, suggest that the unit that is identified as the basic unit of speech production is influenced by the nature of the speech that is being studied, i.e., real words as compared to other real words, pseudowords as compared to other pseudowords, or real words as compared to pseudowords.     

Short-term retention of lexical-semantic representations: implications for speech production

Patients with semantic STM deficits have difficulty comprehending sentences that require the retention of several lexical-semantic representations prior to their integration into higher-level propositions (Martin, 1995: Martin & Romani. 1994). In Experiment 1, patients with a semantic retention deficit had difficulty with the same type of constructions in speech production, namely noun phrases with one or two prenominal adjectives. Their performance improved when they could produce the nouns and adjectives in sentence form, which placed smaller demands on lexical-semantic retention. In Experiment 2 these patients were better able to produce syntactically complex sentences than the prenominal adjective phrases having an equal number of content words, indicating that the findings in Experiment 1 could not be attributed to syntactic complexity. These patients produced more pauses in the sentence constructions in Experiments 1 and 2, suggesting that the timing of such productions is abnormal. In contrast, patient EA, with a phonological retention deficit, performed better than the patients with a semantic retention deficit on the AN phrases despite having a smaller STM span. She showed no significant benefit of producing sentence compared to phrase constructions, and also made fewer and shorter pauses than the other patients. These findings support the multiple capacities view of verbal working memory and suggest that the same semantic retention capacity used in language comprehension is used in speech production.     

Functional anatomy of speech perception and speech production: psycholinguistic implications

This paper presents evidence for a new model of the functional anatomy of speech/language (Hickok & Poeppel, 2000) which has, at its core, three central claims: (1) Neural systems supporting the perception of sublexical aspects of speech are essentially bilaterally organized in posterior superior temporal lobe regions; (2) neural systems supporting the production of phonemic aspects of speech comprise a network of predominately left hemisphere systems which includes not only frontal regions, but also superior temporal lobe regions; and (3) the neural systems supporting speech perception and production partially overlap in left superior temporal lobe. This model, which postulates nonidentical but partially overlapping systems involved in the perception and production of speech, explains why psycho- and neurolinguistic evidence is mixed regarding the question of whether input and output phonological systems involve a common network or distinct networks.     

Effects of syllable frequency in speech production

In the speech production model proposed by [Levelt, W. J. M., Roelofs, A., Meyer, A. S. (1999). A theory of lexical access in speech production. Behavioral and Brain Sciences, 22, pp. 1-75.], syllables play a crucial role at the interface of phonological and phonetic encoding. At this interface, abstract phonological syllables are translated into phonetic syllables. It is assumed that this translation process is mediated by a so-called Mental Syllabary. Rather than constructing the motor programs for each syllable on-line, the mental syllabary is hypothesized to provide pre-compiled gestural scores for the articulators. In order to find evidence for such a repository, we investigated syllable-frequency effects: If the mental syllabary consists of retrievable representations corresponding to syllables, then the retrieval process should be sensitive to frequency differences. In a series of experiments using a symbol-position association learning task, we tested whether high-frequency syllables are retrieved and produced faster compared to low-frequency syllables. We found significant syllable frequency effects with monosyllabic pseudo-words and disyllabic pseudo-words in which the first syllable bore the frequency manipulation; no effect was found when the frequency manipulation was on the second syllable. The implications of these results for the theory of word form encoding at the interface of phonological and phonetic encoding; especially with respect to the access mechanisms to the mental syllabary in the speech production model by (Levelt et al.) are discussed.     

The intermodal representation of speech in newborns

It has been proposed that speech is specified by the eye, the ear, and even the skin. Kuhl and Meltzoff (1984) showed that 4-month-olds could lip-read to an extent. Given the age of the infants, it was not clear whether this was a learned skill or a by-product of the primary auditory process. This paper presents evidence that neonate infants (less than 33 h) show virtually identical patterns of intermodal interaction as do 4-month-olds. Since they are neonates, it is unlikely that learning was involved. The results indicate that human speech is specified by both eye and ear at an age when built-in structural sensitivities provide the most plausible explanation.     

The psychological representation of speech sounds

If one listens to a meaningless syllable that is repeated over and over, he will hear it undergo a variety of changes. These changes are extremely systematic in character and can be described phonetically in terms of reorganizations of the phones constituting the syllable and changes in a restricted set of distinctive features. When a new syllable is presented to a subject after he has listened to a particular syllable that was repeated, he will misreport the new (test) syllable. His misperception of the test syllable is related to the changes occurring in the representation of the original repeated syllable just prior to the presentation of the test syllable.     

The effect of SpeechEasy on stuttering frequency, speech rate, and speech naturalness

The effects of SpeechEasy on stuttering frequency, stuttering severity self-ratings, speech rate, and speech naturalness for 31 adults who stutter were examined. Speech measures were compared for samples obtained with and without the device in place in a dispensing setting. Mean stuttering frequencies were reduced by 79% and 61% for the device compared to the control conditions on reading and monologue tasks, respectively. Mean severity self-ratings decreased by 3.5 points for oral reading and 2.7 for monologue on a 9-point scale. Despite dramatic reductions in stuttering frequency, mean global speech rates in the device condition increased by only 8% in the reading task and 15% for the monologue task, and were well below normal. Further, complete elimination of stuttering was not associated with normalized speech rates. Nevertheless, mean ratings of speech naturalness improved markedly in the device compared to the control condition and, at 3.3 and 3.2 for reading and monologue, respectively, were only slightly outside the normal range. These results show that SpeechEasy produced improved speech outcomes in an assessment setting. However, findings raise the issue of a possible contribution of slowed speech rate to the stuttering reduction effect, especially given participants' instructions to speak chorally with the delayed signal as part of the active listening instructions of the device protocol. Study of device effects in situations of daily living over the long term is necessary to fully explore its treatment potential, especially with respect to long-term stability. Educational objectives: The reader will be able to discuss and evaluate: (1) issues pertinent to evaluating treatment benefits of fluency aids and (2) the effects of SpeechEasy on stuttering frequency, speech rate, and speech naturalness during testing in a dispensing setting for a relatively large sample of adults who stutter.     

Effects of syllable structure in aphasic errors: implications for a new model of speech production

Current models of word production assume that words are stored as linear sequences of phonemes which are structured into syllables only at the moment of production. This is because syllable structure is always recoverable from the sequence of phonemes. In contrast, we present theoretical and empirical evidence that syllable structure is lexically represented. Storing syllable structure would have the advantage of making representations more stable and resistant to damage. On the other hand, re-syllabifications affect only a minimal part of phonological representations and occur only in some languages and depending on speech register. Evidence for these claims comes from analyses of aphasic errors which not only respect phonotactic constraints, but also avoid transformations which move the syllabic structure of the word further away from the original structure, even when equating for segmental complexity. This is true across tasks, types of errors, and, crucially, types of patients. The same syllabic effects are shown by apraxic patients and by phonological patients who have more central difficulties in retrieving phonological representations. If syllable structure was only computed after phoneme retrieval, it would have no way to influence the errors of phonological patients. Our results have implications for psycholinguistic and computational models of language as well as for clinical and educational practices.     

Change of intensity fails to produce an irrelevant sound effect: implications for the representation of unattended sound.

Sequences of changing sounds that are irrelevant to the task at hand disrupt serial recall appreciably even though participants are instructed to ignore the sounds. Three experiments, which compared the effect of changing token identity with that of changing intensity in the 55- to 85-dB (A) range, were conducted. Although serial recall was impaired by changes in token identity, no disruptive effects of a change in intensity were found. This was replicated using speech and nonspeech. Overall, the absence of a changing intensity effect was based on an analysis of the performance of 115 participants in a design whose power was .98. This outcome suggests that the representation of intensity in preattentive processing of auditory stimuli is somewhat different from that of other acoustic features.     

Phonological similarity and the irrelevant speech effect: implications for models of short-term verbal memory

Three experiments studied the interaction between irrelevant speech and phonological similarity within both the remembered and the irrelevant auditory material. Phonological similarity within the remembered list impaired performance in both baseline and irrelevant speech conditions, whereas phonological similarity between the remembered and ignored irrelevant items did not influence performance. Although there was a tendency for similarity within the irrelevant items to reduce interference, this proved to be a less robust finding. Implications for the theoretical interpretation of the irrelevant speech effect are discussed.     

Utterance format affects phonological priming in the picture-word task: implications for models of phonological encoding in speech production

Picture-word experiments investigating the production of multiword utterances with distractors that are phonologically related to words in noninitial position have yielded inconsistent results, ranging from facilitation to inhibition. A comparison of these studies is complicated by differences in detail. In parallel to the empirical inconsistencies, different theoretical accounts of phonological encoding in speech production have been provided. In the present article, the authors propose a unitary account, which can in principle account for facilitation, null effects, and inhibition. It assumes a graded activation pattern of the elements within the scope of phonological advance planning. The account is tested in an experiment varying utterance format while keeping all other aspects constant. The results are consistent with the proposed unitary account.     

口语产生中词频效应、音节频率效应和语音促进效应的认知年老化

采用图画-词汇干扰实验范式,考察了汉语口语产生过程中词频与音节频率效应、语音促进效应的认知年老化现象及其认知机制。结果发现,老年组的图画命名时间长于青年组,且老年组的词频效应和音节频率效应高于青年组,而语音相关效应低于青年组。老年组中词频和音节频率存在两因素交互作用,青年组则没有,这表明随着年龄增加,老年人的心理词典中不仅语义水平和音韵水平之间的联结强度变弱,而且信息之间的作用模式发生了变化。研究结果为激活不充分假设或传输不足假设提供了证据。     

The effect of fast speech rate on stuttering frequency during delayed auditory feedback

Delayed auditory feedback (DAF) has been documented to improve fluency in those who stutter. The increased fluency has been attributed to the slowed speech rate induced by DAF, but recent experiments have suggested that increasing the speech rate may also decrease stuttering under DAF. This investigation described the effect of combining a fast speech rate and DAF on the fluency of four people who stutter. Fluency of the two mildly dysfluent subjects was the same for both no DAF and DAF conditions at normal and at fast oral reading rates. In contrast, the two severely dysfluent subjects improved in fluency from the no DAF to the DAF conditions. They were found to be dysfluent at both normal and fast oral reading rates without DAF. The results of the study point to the need for further research on the relationship between speech rate and stuttering frequency under conditions of DAF and no DAF. EDUCATIONAL OBJECTIVES: Readers will learn about and be able to describe how the frequency of stuttering is affected by: (1) speech rates; (2) DAF; and (3) how stuttering severity influences such effects.     

Levels of representation in the electrophysiology of speech perception

Mapping from acoustic signals to lexical representations is a complex process mediated by a number of different levels of representation. This paper reviews properties of the phonetic and phonological levels, and hypotheses about how category structure is represented at each of these levels, and evaluates these hypotheses in light of relevant electrophysiological studies of phonetics and phonology. The paper examines evidence for two alternative views of how infant phonetic representations develop into adult representations, a structure-changing view and a structure-adding view, and suggests that each may be better suited to different kinds of phonetic categories. Electrophysiological results are beginning to provide information about phonological representations, but less is known about how the more abstract representations at this level could be coded in the brain.     

Determinants of lexical access in speech production: Role of word frequency and age of acquisition

The main determinants of lexical access in speech are considered to be a word's age of acquisition (AoA) and its frequency of occurrence in a speaker's experience. It is unclear whether and how these variables interact, although they are commonly observed to be correlated, for the few studies that address the issue have reported inconsistent findings. An influential view of AoA in lexical processing (Ellis and Lambon Ralph, 2000) predicts stronger frequency effects for items acquired later in life than for those acquired at an early age. Five experiments were designed to investigate the possible interaction of AoA and frequency effects in speech. We found that the interaction between word frequency and AoA was not robust and that, contrary to expectation, the effect of word frequency was greater for words acquired earlier in life than for those acquired later. The implications of our findings are discussed.     

The facilitative influence of phonological similarity and neighborhood frequency in speech production in younger and older adults

A tip-of-the-tongue (TOT) elicitation task and a picture-naming task were used to examine the role of neighborhood frequency as well as word frequency and neighborhood density in speech production. As predicted for the younger adults in Experiment 1, more TOT states were elicited for words with low word frequency and with sparse neighborhoods. Contrary to predictions, neighborhood frequency did not significantly influence retrieval of the target word. For the older adults in Experiment 2, however, more TOT states were elicited for words with low neighborhood frequency. Furthermore, in Experiment 3, pictures with high neighborhood frequency were named more quickly and accurately than pictures with low neighborhood frequency. These results show that the number of neighbors and the frequency of those neighbors influence lexical retrieval in speech production. The facilitative nature of these factors is more parsimoniously accounted for by an interactive model rather than by a strictly feedforward model of speech production.