A speech-rate intelligibility threshold for speeded and time-compressed connected speech

An automated threshold method has been developed for determining the maximum rate of speech understood by individual listeners. Two experiments were undertaken to determine whether the threshold was related to the comprehension of speech or to speech intelligibility. The first experiment compared thresholds of two types of rapid speech reportedly different in intelligibility: simple speeded speech and speech compressed by the sampling method. The second experiment sought to determine the relationship of the threshold to traditional comprehension measures. The results are discussed in terms of the intelligibility and comprehensibility of speech.     

Adaptation to time-compressed speech: phonological determinants

Perceptual adaptation to time-compressed speech was analyzed in two experiments. Previous research has suggested that this adaptation phenomenon is language specific and takes place at the phonological level. Moreover, it has been proposed that adaptation should only be observed for languages that are rhythmically similar. This assumption was explored by studying adaptation to different time-compressed languages in Spanish speakers. In Experiment 1, the performances of Spanish-speaking subjects who adapted to Spanish, Italian, French, English, and Japanese were compared. In Experiment 2, subjects from the same population were tested with Greek sentences compressed to two different rates. The results showed adaptation for Spanish, Italian, and Greek and no adaptation for English and Japanese, with French being an intermediate case. To account for the data, we propose that variables other than just the rhythmic properties of the languages, such as the vowel system and/or the lexical stress pattern, must be considered. The Greek data also support the view that phonological, rather than lexical, information is a determining factor in adaptation to compressed speech.     

Dissociations in perceptual learning revealed by adult age differences in adaptation to time-compressed speech

When presented with several time-compressed sentences, young adults' performance improves with practice. Such adaptation has not been studied in older adults. To study age-related changes in perceptual learning, the authors tested young and older adults' ability to adapt to degraded speech. First, the authors showed that older adults, when equated for starting accuracy with young adults, adapted at a rate and magnitude comparable to young adults. However, unlike young adults, older adults failed to transfer this learning to a different speech rate and did not show additional benefit when practice exceeded 20 sentences. Listeners did not adapt to speech degraded by noise, indicating that adaptation to time-compressed speech was not attributable to task familiarity. Finally, both young and older adults adapted to spectrally shifted noise-vocoded speech. The authors conclude that initial perceptual learning is comparable in young and older adults but maintenance and transfer of this learning decline with age.     

Perceptual adjustment to time-compressed speech: A cross-linguistic study

Previous research has shown that, when hearers listen to artificially speeded speech, their performance improves over the course of 10–15 sentences, as if their perceptual system was “adapting” to these fast rates of speech. In this paper, we further investigate the mechanisms that are responsible for such effects. In Experiment 1, we report that, for bilingual speakers of Catalan and Spanish, exposure to compressed sentences in either language improves performance on sentences in the other language. Experiment 2 reports that Catalan/Spanish transfer of performance occurs even in monolingual speakers of Spanish who do not understand Catalan. In Experiment 3, we study another pair of languages— namely, English and French—and report no transfer of adaptation between these two languages for English—French bilinguals. Experiment 4, with monolingual English speakers, assesses transfer of adaptation from French, Dutch, and English toward English. Here we find that there is no adaptation from French and intermediate adaptation from Dutch. We discuss the locus of the adaptation to compressed speech and relate our findings to other cross-linguistic studies in speech perception.     

Children's Use of Generics in Inductive Inferences

Online comprehension of naturally spoken and perceptually degraded words was assessed in 95 children ages 12 to 31 months. The time course of word recognition was measured by monitoring eye movements as children looked at pictures while listening to familiar target words presented in unaltered, time-compressed, and low-pass-filtered forms. Success in word recognition varied with age and level of vocabulary development, and with the perceptual integrity of the word. Recognition was best overall for unaltered words, lower for time-compressed words, and significantly lower in low-pass-filtered words. Reaction times were fastest in compressed, followed by unaltered and filtered words. Results showed that children were able to recognize familiar words in challenging conditions and that productive vocabulary size was more sensitive than chronological age as a predictor of children's accuracy and speed in word recognition.     

Dynamics of Word Comprehension in Infancy: Developments in Timing, Accuracy, and Resistance to Acoustic Degradation

Online comprehension of naturally spoken and perceptually degraded words was assessed in 95 children ages 12 to 31 months. The time course of word recognition was measured by monitoring eye movements as children looked at pictures while listening to familiar target words presented in unaltered, time-compressed, and low-pass-filtered forms. Success in word recognition varied with age and level of vocabulary development, and with the perceptual integrity of the word. Recognition was best overall for unaltered words, lower for time-compressed words, and significantly lower in low-pass-filtered words. Reaction times were fastest in compressed, followed by unaltered and filtered words. Results showed that children were able to recognize familiar words in challenging conditions and that productive vocabulary size was more sensitive than chronological age as a predictor of children's accuracy and speed in word recognition.     

语音超文本系统中锚点标记方式的比较研究

近年来。语音超文本系统中超链接锚点的标记方式成为该研究领域的一个热点问题。笔者在设计参数优化基础上对语音超文本系统中常见的两种超链接锚点标记方式——言语相关标记与非言语相关标记进行比较研究,旨在为语音超文本界面中超链接锚点标记的设计提供适宜的参数。实验在模拟的语音超文本系统中进行,以链接词检测率、句子理解正确率和主观评价作为评价绩效的指标,结果发现,(1)男女声变调的言语相关标记方式下对链接词的检测率和主观评价均优于全词标记和尾字标记两种非言语相关标记方式,但上述三种标记方式对句子理解均无显著影响;(2)采用非言语相关标记时,链接词在句中的位置显著影响其检测率。根据上述结果,笔者推荐男女声变调标记可作为语音超文本链接词标记的首选方式。     

Regaining lost time: adult aging and the effect of time restoration on recall of time-compressed speech.

Two experiments in which time was restored to artificially accelerated (time-compressed) speech are reported. Experiment 1 showed that although both young and older adults' recall of the speech benefited from the restoration of time, time restoration failed to boost the older adults to their baseline levels for unaltered speech. In Experiment 2, either 100% or 125% of lost time was restored by inserting pauses, either at linguistic boundaries or at random points within the passages. Experiment 2 showed that the beneficial effects of time restoration depended on where processing time was inserted, as well as how much time was restored. Results are interpreted in terms of age-related slowing in speech processing moderated by preserved linguistic knowledge and short-term conceptual memory.     

Speech comprehension difficulties in older adults: cognitive slowing or age-related changes in hearing?

Speech comprehension declines more rapidly in older adults than in younger adults as speech rate increases. This effect is usually attributed to a slowing of brain function with age. Alternatively, this Age X Speed interaction could reflect the inability of the older adult's auditory system to cope with speed-induced stimulus degradation. When the authors speeded speech in a way that produced minimal degradation, both age groups were equally affected. However, when speech was speeded using other methods, word identification declined more in older than in younger adults. Hence, auditory decline rather than cognitive slowing may be responsible for older adults' poorer performance in speeded conditions.     

Measuring automatic retrieval in a conceptual priming task

The speeded response technique has demonstrated that priming in perceptual memory tasks can occur through automatic retrieval that is uncontaminated by conscious retrieval (pure automatic retrieval). This work assesses whether priming in a conceptual task (category exemplar generation) can occur through pure automatic retrieval using the same technique. Automatic retrieval estimates obtained using the speeded response technique were compared to those obtained using more traditional measures (implicit memory and process dissociation procedure [PDP]). Similar estimates of automatic retrieval were obtained for speeded, implicit, and PDP groups following shallow processing. However, higher estimates of automatic retrieval were obtained following deep processing in the speeded and implicit conditions compared to the PDP condition. Advantages for using the speeded response technique to index automatic memory are discussed.     

Age and understanding speakers with Spanish or Taiwanese accents

This pilot study concerned the intelligibility of accented speech for listeners of different ages. 72 native speakers of English, representing three age groups (20-39, 40-59, 60 and older) listened to words and sentences produced by native speakers of English, Taiwanese, and Spanish. Listeners transcribed words and sentences. Listeners also rated speakers' comprehensibility, i.e., listeners' perceptions of difficulty in understanding utterances, and accentedness, i.e., how strong a speaker's foreign accent is perceived to be. On intelligibility measures, older adults had significantly greater difficulty in understanding individuals with accented speech than the other two age groups. Listeners, regardless of age, were more likely to provide correct responses if they perceived the speaker easier to understand. Ratings of comprehensibility were highly correlated with ratings of accentedness.     

Listening rate and comprehension as a function of preference for and exposure to time-altered speech

We conducted experiments on the effects of brief prior exposure to time-altered speech on preferred listening rate and the rate listeners would select when asked to listen to speech as fast as possible with good compression (induced listening rate). In Exp. 1, 48 participants were exposed either to normal rate speech or to speech compressed to twice-normal rate. Brief exposure to twice-normal rate speech led to a faster induced listening rate than exposure to normal rate speech. In Exp. 2, 31 participants were briefly exposed to normal rate speech, speech compressed to twice-normal rate, or speech expanded to half-normal rate. The faster the rate of the exposure speech, the faster the induced rate. Speech compressed to twice-normal rate led to a faster induced listening rate than exposure to speech expanded to half-normal rate. Normal rate speech was intermediate between twice-normal and half-normal rate and did not differ significantly from them. Induced listening rate was a linear combination of listening rate preference and recent forced exposure to time-altered speech.     

Speech Perception Among School-Aged Skilled and Less Skilled Readers

This study investigated the relationship between speech perception, phonological processing and reading skills among school-aged children classified as ‘skilled’ and ‘less skilled’ readers based on their ability to read words, decode non-words, and comprehend short passages. Three speech perception tasks involving categorization of speech continua differing in voicing, place and manner of articulation were administered and compared to phonological processing skills in phonological awareness, speeded naming and verbal short-term memory. The results obtained suggested that (a) speech categorization among skilled readers differed from that of less skilled readers, (b) speech perception skills were associated with both reading and phonological processing skills among both skilled and less skilled readers, however, (c) a strong association between speeded naming and both word and passage reading skills found among skilled readers was absent among less skilled readers. These results suggested that phonological representations and/or activation may not be as well developed in less skilled readers.     

Subliminal speech priming

We present a novel subliminal priming technique that operates in the auditory modality. Masking is achieved by hiding a spoken word within a stream of time-compressed speechlike sounds with similar spectral characteristics. Participants were unable to consciously identify the hidden words, yet reliable repetition priming was found. This effect was unaffected by a change in the speaker's voice and remained restricted to lexical processing. The results show that the speech modality, like the written modality, involves the automatic extraction of abstract word-form representations that do not include nonlinguistic details. In both cases, priming operates at the level of discrete and abstract lexical entries and is little influenced by overlap in form or semantics.     

Measuring automatic retrieval: a comparison of implicit memory, process dissociation, and speeded response procedures

Using the stem completion task, we compared estimates of automatic retrieval from an implicit memory task, the process dissociation procedure, and the speeded response procedure. Two standard manipulations were employed. In Experiment 1, a depth of processing effect was found on automatic retrieval using the speeded response procedure although this effect was substantially reduced in Experiment 2 when lexical processing was required of all words. In Experiment 3, the speeded response procedure showed an advantage of full versus divided attention at study on automatic retrieval. An implicit condition showed parallel effects in each study, suggesting that implicit stem completion may normally provide a good estimate of automatic retrieval. Also, we replicated earlier findings from the process dissociation procedure, but estimates of automatic retrieval from this procedure were consistently lower than those from the speeded response procedure, except when conscious retrieval was relatively low. We discuss several factors that may contribute to the conflicting outcomes, including the evidence for theoretical assumptions and criterial task differences between implicit and explicit tests.     

Auditory processing and cluttering in young children

This study examined the differences among scores on four tests of auditory processing of 6 children who clutter and 6 control subjects matched for age, sex, and grade. Scores on a consonant-vowel dichotic listening task indicated that directing the attention of the attended ear improved the percentage of correct responses for both groups of children. Those who clutter, however, showed a greater percentage of change during the directed right and left ear conditions. Cluttering children performed poorer on right and left competing conditions of the Staggered Spondaic Word Test. No differences were found between groups for the auditory attention task and the time-compressed speech task. Implications for processing of dichotic stimuli and diagnosis of children who clutter are discussed.     

Identification of time-compressed sentential stimuli by good vs poor readers

Ability of eight good and eight poor readers (in Grade 1, ages ranging from 6.7 to 7.4 yr.) to discriminate phonemic contrasts presented in 50% time-compressed sentential stimuli (Subtest 13 of the Carrow-Auditory Visual Abilities Test) was measured. Good readers exhibited a significantly higher over-all mean performance than poor readers on the time-compressed task. Effects of time-compression on the perception of manner, place, voicing and frequency contrasts showed a similar pattern of errors for both groups of readers. Implications of the effects of auditory discrimination on reading abilities are discussed.     

The Effect of Time-Compressed Speech on Comprehensive,Interpretive, and Short-Term Listening

Although contemporary theorists view listening as a multidimensional process, the preponderance of published empirical research on human comprehension of speeded speech is based on an outdated, unitary construct. In the present study, the impact of varying levels of time compression on three different types of listening is investigated. The results indicate that comprehensive listening performance deteriorates significantly as speech compression levels are increased while interpretive and short-term listening performance remains stable until a high degree of time compression (60%) is reached. Explanations for these findings are advanced based upon established differences between short and long-term memory processes.     

Tasks and timing in the perception of linguistic anomaly

Three experiments were conducted to investigate the relative timing of syntactic and pragmatic anomaly detection during sentence processing. Experiment 1 was an eye movement study. Experiment 2 employed a dual-task paradigm with compressed speech input, to put the processing routines under time pressure. Experiment 3 used compressed speech input in an anomaly monitoring task. The outcomes of these experiments suggest that there is little or no delay in pragmatic processing relative to syntactic processing in the comprehension of unambiguous sentences. This narrows the possible explanations for any delays that are observed in the use of pragmatic information for ambiguity resolution.The research reported in this paper was supported by Program Project Grant HD-01994 to Haskins Laboratories from the National Institutes of Child and Human Development, and in part by a grant to Stephen Crain and Donald Shankweiler from the University of Connecticut Research Foundation. We thank Jacques Mehler and Gerry Altmann for helpful information about speech compression algorithms. We are especially grateful to Ignatius Mattingly for his generous expert advice on speech compression and design of the experimental materials, and also for recording all the speech stimuli. Julie Boland, Brian McElree, Janet Nicol, and Martin Pickering provided very helpful advice on an earlier draft.     

Perception of Native English Reduced Forms in Adverse Environments by Chinese Undergraduate Students

Previous research has shown that learners of English-as-a-second-language (ESL) have difficulties in understanding connected speech spoken by native English speakers. Extending from past research limited to quiet listening condition, this study examined the perception of English connected speech presented under five adverse conditions, namely multi-talker babble noise, speech-shaped noise, factory noise, whispering and sad emotional tones. We tested a total of 64 Chinese ESL undergraduate students, using a battery of listening tasks. Results confirmed that the recognition of English native speech was more challenging for Chinese ESL learners under unfavorable listening conditions, in comparison to a noise-free listening condition. These findings carry significant implications for the importance of training and assessments on connected speech perception across various listening environments.