Do speakers have access to a mental syllabary?

The first, theoretical part of this paper sketches a framework for phonological encoding in which the speaker successively generates phonological syllables in connected speech. The final stage of this process, phonetic encoding, consists of accessing articulatory gestural scores for each of these syllables in a “mental syllabary”. The second, experimental part studies various predictions derived from this theory. The main finding is a syllable frequency effect: words ending in a high-frequent syllable are named faster than words ending in a low-frequent syllable. As predicted, this syllable frequency effect is independent of and additive to the effect of word frequency on naming latency. The effect, moreover, is not due to the complexity of the word-final syllable. In the General Discussion, the syllabary model is further elaborated with respect to phonological underspecification and activation spreading. Alternative accounts of the empirical findings in terms of core syllables and demisyllables are considered.     

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.     

Syllable frequency and syllable structure in apraxia of speech

Recent accounts of the pathomechanism underlying apraxia of speech (AOS) were based on the speech production model of Levelt, Roelofs, and Meyer, and Meyer (1999)1999. The apraxic impairment was localized to the phonetic encoding level where the model postulates a mental store of motor programs for high-frequency syllables. Varley and Whiteside (2001a) assumed that in patients with AOS syllabic motor programs are no longer accessible and that these patients are required to use a subsyllabic encoding route. In this study, we tested this hypothesis by exploring the influence of syllable frequency and syllable structure on word repetition in 10 patients with AOS. A significant effect of syllable frequency on error rates was found. Moreover, apraxic errors on consonant clusters were influenced by their position relative to syllable boundaries. These results demonstrate that apraxic patients have access to the syllabary, but that they fail to retrieve the syllabic motor patterns correctly. Our findings are incompatible with a subsyllabic route model of apraxia of speech.     

Picture–word interference reveals inhibitory effects of syllable frequency on lexical selection

While previous research has shown that high syllable frequency can facilitate speech production at the level of phonological/phonetic encoding, little is known about its influence on prephonological processes, specifically lexical selection. The current study used a picture–word interference (PWI) task to (a) shed light on the stages of lexical access where syllable frequency is relevant, and (b) inform as to whether lexical selection is accomplished via competition among activated word options. Participants named pictures whose names had high-frequency (HF) and low-frequency (LF) first syllables while ignoring phonologically related (same first syllable) or unrelated distractor words that were presented simultaneously. Word frequency was also manipulated, as half of the targets were HF words, and half were LF words. Results revealed inhibitory syllable frequency effects in all conditions, such that targets with HF first syllables were named more slowly than targets with LF first syllables. However, inhibitory syllable frequency effects were exacerbated in conditions thought to reflect heightened lexical competition, specifically in the presence of phonologically related distractors and for targets with low word frequency. These findings reveal novel evidence for first-syllable frequency effects on lexical selection and offer further support for models proposing delays at lexical selection due to activation of nontarget competitors.     

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.     

Tip-of-the-tongue states reveal age differences in the syllable frequency effect

Syllable frequency has been shown to facilitate production in some languages but has yielded inconsistent results in English and has never been examined in older adults. Tip-of-the-tongue (TOT) states represent a unique type of production failure where the phonology of a word is unable to be retrieved, suggesting that the frequency of phonological forms, like syllables, may influence the occurrence of TOT states. In the current study, we investigated the role of first-syllable frequency on TOT incidence and resolution in young (18-26 years of age), young-old (60-74 years of age), and old-old (75-89 years of age) adults. Data from 3 published studies were compiled, where TOTs were elicited by presenting definition-like questions and asking participants to respond with "Know," "Don't Know," or "TOT." Young-old and old-old adults, but not young adults, experienced more TOTs for words beginning with low-frequency first syllables relative to high-frequency first syllables. Furthermore, age differences in TOT incidence occurred only for words with low-frequency first syllables. In contrast, when a prime word with the same first syllable as the target was presented during TOT states, all age groups resolved more TOTs for words beginning with low-frequency syllables. These findings support speech production models that allow for bidirectional activation between conceptual, lexical, and phonological forms of words. Furthermore, the age-specific effects of syllable frequency provide insight into the progression of age-linked changes to phonological processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved).     

The syllable’s role in word naming

In a series of experiments, the masked priming paradigm with very brief prime exposures was used to investigate the role of the syllable in the production of English. Experiment 1 (word naming task) showed a syllable priming effect for English words with clear initial syllable boundaries (such as BALCONY), but no effect with ambisyllabic words targets (such as BALANCE, where the /l/ belongs to both the first and the second syllables). Experiment 2 failed to show such syllable priming effects in the lexical decision task. Experiment 3 demonstrated that for words with clear initial syllable boundaries, naming latencies were faster only when primes formed the first syllable of the target, in comparison with a neutral condition. Experiment 4 showed that the two possible initial syllables of ambisyllabic words facilitated word naming to the same extent, in comparison with the neutral condition. Finally, Experiment 5 demonstrated that the syllable priming effect obtained for CV words with clear initial syllable boundaries (such as DIVORCE) was not due to increased phonological and/or orthographic overlap. These results, showing that the syllable constitutes a unit of speech production in English, are discussed in relation to the model of phonological and phonetic encoding proposed by Levelt and Wheeldon (1994).     

Planning and articulation in incremental word production: syllable-frequency effects in English

We investigated the role of syllables during speech planning in English by measuring syllable-frequency effects. So far, syllable-frequency effects in English have not been reported. English has poorly defined syllable boundaries, and thus the syllable might not function as a prominent unit in English speech production. Speakers produced either monosyllabic (Experiment 1) or disyllabic (Experiment 2-4) pseudowords as quickly as possible in response to symbolic cues. Monosyllabic targets consisted of either high- or low-frequency syllables, whereas disyllabic items contained either a 1st or 2nd syllable that was frequency-manipulated. Significant syllable-frequency effects were found in all experiments. Whereas previous findings for disyllables in Dutch and Spanish-languages with relatively clear syllable boundaries-showed effects of a frequency manipulation on 1st but not 2nd syllables, in our study English speakers were sensitive to the frequency of both syllables. We interpret this sensitivity as an indication that the production of English has more extensive planning scopes at the interface of phonetic encoding and articulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved).     

Aspects of the syntax of behavior: Syllable structure and speech rate

This paper shows that maximal rate of speech varies as a function of syllable structure. For example, CCV syllables such as [sku] and CVC syllables such as [kus] are produced faster than VCC syllables such as [usk] when subjects repeat these syllables as fast as possible. Spectrographic analyses indicated that this difference in syllable duration was not confined to any one portion of the syllables: the vowel, the consonants and even the interval between syllable repetitions was longer for VCC syllables than for CVC and CCV syllables. These and other findings could not be explained in terms of word frequency, transition frequency of adjacent phonemes, or coarticulation between segments. Moreover, number of phonemes was a poor predictor of maximal rate for a wide variety of syllable structures, since VCC structures such as [ulk] were produced slower than phonemically longer CCCV structures such as [sklu], and V structures such as [a] were produced no faster than phonemically longer CV structures such as [ga]. These findings could not be explained by traditional models of speech production or articulatory difficulty but supported a complexity metric derived from a recently proposed theory of the serial production of syllables. This theory was also shown to be consistent with the special status of CV syllables suggested by Jakobson as well as certain aspects of speech errors, tongue-twisters and word games such as Double Dutch.     

Interaction and representational integration: evidence from speech errors

We examine the mechanisms that support interaction between lexical, phonological and phonetic processes during language production. Studies of the phonetics of speech errors have provided evidence that partially activated lexical and phonological representations influence phonetic processing. We examine how these interactive effects are modulated by lexical frequency. Previous research has demonstrated that during lexical access, the processing of high frequency words is facilitated; in contrast, during phonetic encoding, the properties of low frequency words are enhanced. These contrasting effects provide the opportunity to distinguish two theoretical perspectives on how interaction between processing levels can be increased. A theory in which cascading activation is used to increase interaction predicts that the facilitation of high frequency words will enhance their influence on the phonetic properties of speech errors. Alternatively, if interaction is increased by integrating levels of representation, the phonetics of speech errors will reflect the retrieval of enhanced phonetic properties for low frequency words. Utilizing a novel statistical analysis method, we show that in experimentally induced speech errors low lexical frequency targets and outcomes exhibit enhanced phonetic processing. We sketch an interactive model of lexical, phonological and phonetic processing that accounts for the conflicting effects of lexical frequency on lexical access and phonetic processing.     

Phonology as the source of syllable frequency effects in visual word recognition: Evidence from French

In order to investigate whether syllable frequency effects in visual word recognition can be attributed to phonologically or orthographically defined syllables, we designed one experiment that allowed six critical comparisons. Whereas only a weak effect was obtained when both orthographic and phonological syllable frequency were conjointly manipulated in Comparison 1, robust effects for phonological and null effects for orthographic syllable frequency were found in Comparisons 2 and 3. Comparisons 4 and 5 showed that the syllable frequency effect does not result from a confound with the frequency of letter or phoneme clusters at the beginning of words. The syllable frequency effect was shown to diminish with increasing word frequency in Comparison 6. These results suggest that visually presented polysyllabic words are parsed into phonologically defined syllables during visual word recognition. Materials and links may be accessed at www.psychonomic.org/archive.     

Monitoring syllable boundaries during speech production

This study investigated the encoding of syllable boundary information during speech production in Dutch. Based on Levelt's model of phonological encoding, we hypothesized segments and syllable boundaries to be encoded in an incremental way. In a self-monitoring experiment, decisions about the syllable affiliation (first or second syllable) of a pre-specified consonant, which was the third phoneme in a word, were required (e.g., ka.No 'canoe' vs. kaN.sel 'pulpit'; capital letters indicate pivotal consonants, dots mark syllable boundaries). First syllable responses were faster than second syllable responses, indicating the incremental nature of segmental encoding and syllabification during speech production planning. The results of the experiment are discussed in the context of Levelt's model of phonological encoding.     

Disorder in sequential speech perception: a case study on pure word deafness

We described disorders of a patient which were uniquely restricted to speech perception of syllable sequences after brain damage. The results of series of experiments using syllable sequences showed "negative recency effect," in which the subject's repetition performance at the latter syllable position was remarkably poor. Experimental analyses suggested that the "negative recency effect" could be due to dual factors: the lower rate of processing of speech sounds and the memory load of holding processes of preceding syllables imposed on the succeeding phonological processing. The results also suggested that the holding processes which imposed the memory load on the succeeding auditory phonological coding processing were modality nonspecific.     

Evidence of Absence: Abstract Metrical Structure in Speech Planning

Rhythmic structure in speech is characterized by sequences of stressed and unstressed syllables. A large body of literature suggests that speakers of English attempt to achieve rhythmic harmony by evenly distributing stressed syllables throughout prosodic phrases. The question remains as to how speakers plan metrical structure during speech production and whether it is planned independently of phonemes. To examine this, we designed a tongue twister task consisting of disyllabic word pairs with overlapping phonological segments and either matching or non-matching metrical structure. Results showed that speakers had more difficulty producing metrically regular word pairs, compared to irregular pairs; that is, word pairs with irregular meter had faster productions and fewer speech errors in this production task. This finding of metrical regularity inhibiting production is inconsistent with an abstract metrical structure that is planned independently of phonemes at the point of phonological encoding.     

The frequency of simultaneous disfluency and phonological errors in children: A preliminary investigation

The frequency of simultaneous disfluency and phonological errors was examined in seven young English-speaking children exhibiting coexisting stuttering and phonological disorders. Data were gathered during 30 minutes of mother-child conversation and analyzed in three parts: (1) stuttering, (2) phonological errors, and (3) stuttering and phonological error co-occurrence. Results indicated that stuttering did not occur more frequently on syllables with phonological errors than on syllables without phonological errors. However, the frequency of disfluency on word-initial consonant clusters with phonological errors was significantly higher than on word-initial consonant clusters without phonological errors. Theoretical and clinical implications are discussed.     

PhonItalia: a phonological lexicon for Italian

In this article, we present the first open-access lexical database that provides phonological representations for 120,000 Italian word forms. Each of these also includes syllable boundaries and stress markings and a comprehensive range of lexical statistics. Using data derived from this lexicon, we have also generated a set of derived databases and provided estimates of positional frequency use for Italian phonemes, syllables, syllable onsets and codas, and character and phoneme bigrams. These databases are freely available from phonitalia.org. This article describes the methods, content, and summarizing statistics for these databases. In a first application of this database, we also demonstrate how the distribution of phonological substitution errors made by Italian aphasic patients is related to phoneme frequency.     

汉语口吃者在不出声言语中的语音编码

口吃者与非口吃者在不出声言语中语音编码的差异是口吃者语音加工异常的有力证据。通过三个实验,分别考察了口吃者与非口吃者监控汉语拼音中声母、韵母及声调的差异。结果表明,口吃者对声母的监控与非口吃者相比没有显著的差异,但在监控韵母及声调时,口吃者的反应显著慢于非口吃者。研究结果支持了关于口吃的“内在修正假说”,对研究汉语的语音编码有启发,对于口吃的诊断和治疗也有重要的启示     

Cross-linguistic differences in the use of durational cues for the segmentation of a novel language

It is widely accepted that duration can be exploited as phonological phrase final lengthening in the segmentation of a novel language, i.e., in extracting discrete constituents from continuous speech. The use of final lengthening for segmentation and its facilitatory effect has been claimed to be universal. However, lengthening in the world languages can also mark lexically stressed syllables. Stress-induced lengthening can potentially be in conflict with right edge phonological phrase boundary lengthening. Thus the processing of durational cues in segmentation can be dependent on the listener’s linguistic background, e.g., on the specific correlates and unmarked location of lexical stress in the native language of the listener. We tested this prediction and found that segmentation by both German and Basque speakers is facilitated when lengthening is aligned with the word final syllable and is not affected by lengthening on either the penultimate or the antepenultimate syllables. Lengthening of the word final syllable, however, does not help Italian and Spanish speakers to segment continuous speech, and lengthening of the antepenultimate syllable impedes their performance. We have also found a facilitatory effect of penultimate lengthening on segmentation by Italians. These results confirm our hypothesis that processing of lengthening cues is not universal, and interpretation of lengthening as a phonological phrase final boundary marker in a novel language of exposure can be overridden by the phonology of lexical stress in the native language of the listener.     

Syllable similarity: The effects of differences in vowels, consonants, and order

In five experiments with synthetic and natural speech syllables, a rating task we used to study the effects of differences in vowels, consonants, and segment order on judged syllable similarity. The results of Experiments I-IV support neither a purely phonemic model of speech representation, in which vowel, consonant, and order are represented independently, nor a purely syllabic model, in which the three factors are integrated. Instead, the data indicate that subjects compare representations in which adjacent vowel and consonant are independent of one another but are not independent of their positions in the syllable. Experiment V provided no support for the hypothesis that this position-sensitive coding is due to acoustic differences in formant transitions.     

Phonologically related lexical repetition disorder: a case study

Errors of repetition in aphasia are most often nonword substitutions. Phonologically related lexical errors, or formal errors, are real-word substitutions that overlap with target words in sound. In the present research we present the case of an aphasic patient, MMB, who produced an unusually high rate of formal paraphasias in repetition. Six experiments were conducted to investigate the combination of impairments contributing to MMB's pattern of repetition and to test the predictions made by two theories of formal errors. MMB's formal errors in repetition were influenced by target frequency, but not by target length or imageability. Formal errors tended to be more frequent than their targets and showed greatest phonological overlap with targets at initial consonant. These findings provided partial support for Martin and Saffran's fully interactive spreading activation account of formal errors and did not support Blanken's phonological interactive encoding account. In Experiment 6, the effect on repetition of increasing auditory verbal short-term memory (AVSTM) demands was examined using a paired word repetition experiment. Under these conditions, MMB produced semantic paraphasias for the first time, providing strong support for the Martin-Saffran hypothesis that phonologically related, and semantic, lexical repetition disorders lie on a continuum of severity moderated by the degree of AVSTM impairment.