Effects of speaker variability and phoneme location on speech perception

The effects of variation in a speaker's voice and temporal phoneme location were assessed through a series of speeded classification experiments. Listeners monitored speech syllables for target consonants or vowels. The results showed that speaker variability and phoneme-location variability had detrimental effects on classification latencies for target sounds. In addition, an interaction between variables showed that the speaker variability effect was obtained only when temporal phoneme location was fixed across trials. A subadditive decrement in latencies produced by the interaction of the two variables was also obtained, suggesting that perceptual loads may not affect perceptual adjustments to a speaker's voice in the same way that memory loads do.     

Articulatory-rate context effects in phoneme identification

Three experiments demonstrated that the pattern of changes in articulatory rate in a precursor phrase can affect the perception of voicing in a syllable-initial prestress velar stop consonant. Fast and slow versions of a 10-word precursor phrase were recorded, and sections from each version were combined to produce several precursors with different patterns of change in articulatory rate. Listeners judged the identity of a target syllable, selected from a 7-member /gi/-ki/ voice-onset-time (VOT) continuum, that followed each precursor phrase after a variable brief pause. The major results were: (a) articulatory-rate effects were not restricted to the target syllable's immediate context; (b) rate effects depended on the pattern of rate changes in the precursor and not the amount of fast or slow speech or the proximity of fast or slow speech to the target syllable: and (c) shortening of the pause (or closure) duration led to a shortening of VOT boundaries rather than a lengthening as previously found in this phonetic context. Results are explained in terms of the role of dynamic temporal expectancies in determining the response to temporal information in speech, and implications for theories of extrinsic vs. intrinsic timing are discussed.     

Effects of orthographic transparency on reading and phoneme awareness in children learning to read in Wales

The relationship between the development of reading skills and the consistency of the orthography (writing system) is investigated in a study that examines reading acquisition in children living in Wales. Performance of children learning to read Welsh (a transparent alphabetic orthography) on tests of reading and phoneme detection was compared with the performance of children learning to read English (an opaque alphabetic orthography). The children were tested during their second year of formal reading instruction at school when they were aged between 5 and 6 years, and again one year later. The children learning to read in Welsh performed significantly better at reading both real words and nonwords than children learning to read in English. The English readers made fewer phonologically based reading errors. The Welsh readers also performed better on a phoneme awareness task. These findings support the claim that children learn to read more quickly in a transparent orthography, and provide further evidence that the consistency of the orthography influences the initial adoption of different strategies for word recognition.     

Orthographic influences on phoneme deletion response times

The aim of this paper is to provide further evidence that orthography plays a central role in phonemic awareness, by demonstrating an orthographic congruency effect in phoneme deletion. In four initial phoneme deletion experiments, adult participants produced the correct response more slowly with orthographically mismatched stimulus-response pairs (e.g., worth-earth) than with matched pairs (e.g., wage-age). This orthographic effect occurred with or without specific instructions to ignore spelling and when stimuli were presented with or without the to-be-deleted sound. In a final experiment, participants made more errors on complex than simple onset items, but there was no interaction with orthographic mismatch. The repeated observation of this robust orthographic effect suggests that participants are at least aware of orthography during phonemic awareness tasks, and it supports the view that phonemic awareness is directly subserved by orthography.     

Processing strategies in a phoneme deletion task

The present study explores the factors underlying competence in a difficult consonant deletion task, using a sample of nine-year-old children whose development had been followed from the age of four. In particular it examines the factors governing use of phonological and orthographic strategies in the deletion task, and the relations between strategy use, current reading and spelling ability, and earlier phonological awareness skills. Processes in consonant deletion are then mapped on to current dual-route models of reading and spelling.     

Orthographic influences on phoneme deletion response times

The aim of this paper is to provide further evidence that orthography plays a central role in phonemic awareness, by demonstrating an orthographic congruency effect in phoneme deletion. In four initial phoneme deletion experiments, adult participants produced the correct response more slowly with orthographically mismatched stimulus–response pairs (e.g., worth–earth) than with matched pairs (e.g., wage–age). This orthographic effect occurred with or without specific instructions to ignore spelling and when stimuli were presented with or without the to-be-deleted sound. In a final experiment, participants made more errors on complex than simple onset items, but there was no interaction with orthographic mismatch. The repeated observation of this robust orthographic effect suggests that participants are at least aware of orthography during phonemic awareness tasks, and it supports the view that phonemic awareness is directly subserved by orthography.     

The nature of phoneme representation in spoken word recognition

Four experiments used the psychological refractory period logic to examine whether integration of multiple sources of phonemic information has a decisional locus. All experiments made use of a dual-task paradigm in which participants made forced-choice color categorization (Task 1) and phoneme categorization (Task 2) decisions at varying stimulus onset asynchronies. In Experiment 1, Task 2 difficulty was manipulated using words containing matching or mismatching coarticulatory cues to the final consonant. The results showed that difficulty and onset asynchrony combined in an underadditive way, suggesting that the phonemic mismatch was resolved prior to a central decisional bottleneck. Similar results were found in Experiment 2 using nonwords. In Experiment 3, the manipulation of task difficulty involved lexical status, which once again revealed an underadditive pattern of response times. Finally, Experiment 4 compared this prebottleneck variable with a decisional variable: response key bias. The latter showed an additive pattern of responses. The experiments show that resolution of phonemic ambiguity can take advantage of cognitive slack time at short asynchronies, indicating that phonemic integration takes place at a relatively early stage of spoken word recognition.     

Effects of dentalization and devoicing of the /z/ phoneme on listeners' judgment of a speaker's sexual orientation

25 undergraduate listeners judged that a male speaker with normal speech, who dentalized (lisped) or devoiced the /z/ phoneme in the context of a sentence, sounded significantly more "gay" in terms of judged sexual orientation than did the same speaker producing /z/ without phonological processes. Speech-language pathologists should be aware of possible social consequences of speech production disorders.     

Explicit syllable and phoneme segmentation in the young child

To write a language, one must first abstract the unit to be used from the acoustic stream of speech. Writing systems based on the meaningless units, syllables and phonemes, were late developments in the history of written language. The alphabetic system, which requires abstraction of the phonemic unit of speech, was the last to appear, evolved from a syllabary and, unlike the other systems, was apparently invented only once. It might therefore be supposed that phoneme segmentation is particularly difficult and more difficult, indeed, than syllable segmentation. Speech research suggests reasons why this may be so. The present study provides direct evidence of a similar developmental ordering of syllable and phoneme segmentation abilities in the young child. By means of a task which required preschool, kindergarten, and first-grade children to tap out the number of segments in spoken utterances, it was found that, though ability in both syllable and phoneme segmentation increased with grade level, analysis into phonemes was significantly harder and perfected later than analysis into syllables. The relative difficulties of the different units of segmentation are discussed in relation to reading acquisition.     

Lexical access of resyllabified words: Evidence from phoneme monitoring

Resyllabification is a phonological process in which consonants are attached to syllables other than those from which they originally came. In four experiments, we investigated whether resyllabified words, such as "my bike is" pronounced as "mai.bai.kis," are more difficult to recognize than nonresyllabified words. Using a phoneme-monitoring task, we found that phonemes in resyllabified words were detected more slowly than those in nonresyllabified words. This difference increased when recognition of the carrier word was made more difficult. Acoustic differences between the target words themselves could not account for the results, because cross-splicing the resyllabified and nonresyllabified carrier words did not change the pattern. However, when nonwords were used as carriers, the effect disappeared. It is concluded that resyllabification increases the lexical-processing demands, which then interfere with phoneme monitoring.     

Discrimination of differences in digitally manipulated phoneme length during speech

The present study investigated differences in the thresholds of phoneme duration in word and sentence contexts by participants' sex. In the word condition, 27 participants listened to two pairs of words in a dual pair discrimination task. One pair contained the same durations of /s/, and the other pair contained different durations of /s/. Participants were to select the pair which contained different durations of /s/ in the words. In the sentence condition, the other set of 27 participants listened to two pairs of sentences and selected the pair containing different durations of /s/ in the sentences. Throughout these tasks, the participants' just-noticeable-difference and trials-to-completion were analyzed. The results showed that the participants demonstrated better performance in detecting just-noticeable-difference in the sentence condition than in the word condition. In addition, a sex difference was found in just-noticeable-difference in both conditions with better performance in men than women. No significant differences in trials-to-completion were found in either condition.     

Musical competence and phoneme perception in a foreign language

We investigated whether musical competence was associated with the perception of foreign-language phonemes. The sample comprised adult native-speakers of English who varied in music training. The measures included tests of general cognitive abilities, melody and rhythm perception, and the perception of consonantal contrasts that were phonemic in Zulu but not in English. Music training was associated positively with performance on the tests of melody and rhythm perception, but not with performance on the phoneme-perception task. In other words, we found no evidence for transfer of music training to foreign-language speech perception. Rhythm perception was not associated with the perception of Zulu clicks, but such an association was evident when the phonemes sounded more similar to English consonants. Moreover, it persisted after controlling for general cognitive abilities and music training. By contrast, there was no association between melody perception and phoneme perception. The findings are consistent with proposals that music- and speech-perception rely on similar mechanisms of auditory temporal processing, and that this overlap is independent of general cognitive functioning. They provide no support, however, for the idea that music training improves speech perception.     

Activation of multiple phoneme associates of graphemes in visual word recognition

One general issue in the domain of visual word recognition is to delineate the nature of readers' knowledge of the print-sound mapping. A more specific question is to determine whether multiple grapheme-phoneme associations are available and activated during the phonological transcoding of a letter string. Evidence for the activation of irregular associations during print-to-sound transcoding, independently from lexical influences, was assessed in a letter detection task by examining performance on target-absent pseudowords. We contrasted two types of pseudowords that could be considered homophone with a real word by application of either grapheme-phoneme correspondence rules or of multiple phonemic activation. Performance on both types of homophones was compared to nonhomophone control pseudowords, strictly equivalent in terms of orthographic similarity to the base words. The finding of a homophony disadvantage for the homophones by multiple activation was interpreted as evidence for multiple phonemic activation in the print-to-sound conversion system.     

Evidence for a late-occurring effect of phoneme repetition during silent reading

Two reading experiments were conducted to investigate the effect of phoneme repetition during silent reading (also referred to as the visual tongue-twister effect, see McCutchen & Perfetti, 1982; Perfetti & McCutchen, 1982) in conjunction with end-of-clause and end-of-sentence wrap-up effects (Just & Carpenter, 1982; Rayner, Sereno, Morris, Schmauder, & Clifton, 1989). In both experiments, reading time was measured on sentences containing either six or zero words sharing the same initial phoneme. Sentences were presented in a phrase-by-phrase moving window, with each phrase either containing one word that involved a repeated phoneme or a matched word not involving a repeated phoneme. The sixth presentation region either contained or did not contain a comma (Experiment 1) or a period (Experiment 2). The results showed that the effect of phoneme repetition occurred relatively late during sentence processing, only after integration processing related to end-of-clause and end-of-sentence wrap-up occurred.