Publications

Abstract

Spoken-word recognition in a nonnative language is particularly difficult where it depends on discrimination between confusable phonemes. Four experiments here examine whether this difficulty is in part due to phantom competition from “near-words” in speech. Dutch listeners confuse English /aelig/ and /ε/, which could lead to the sequence daf being interpreted as deaf, or lemp being interpreted as lamp. In auditory lexical decision, Dutch listeners indeed accepted such near-words as real English words more often than English listeners did. In cross-modal priming, near-words extracted from word or phrase contexts (daf from DAFfodil, lemp from eviL EMPire) induced activation of corresponding real words (deaf; lamp) for Dutch, but again not for English, listeners. Finally, by the end of untruncated carrier words containing embedded words or near-words (definite; daffodil) no activation of the real embedded forms (deaf in definite) remained for English or Dutch listeners, but activation of embedded near-words (deaf in daffodil) did still remain, for Dutch listeners only. Misinterpretation of the initial vowel here favoured the phantom competitor and disfavoured the carrier (lexically represented as containing a different vowel). Thus, near-words compete for recognition and continue competing for longer than actually embedded words; nonnative listening indeed involves phantom competition.

Abstract

A visual fixation study tested whether seven-month-olds can discriminate between different talkers. The infants were first habituated to talkers producing sentences in either a familiar or unfamiliar language, then heard test sentences from previously unheard speakers, either in the language used for habituation, or in another language. When the language at test mismatched that in habituation, infants always noticed the change. When language remained constant and only talker altered, however, infants detected the change only if the language was the native tongue. Adult listeners with a different native tongue than the infants did not reproduce the discriminability patterns shown by the infants, and infants detected neither voice nor language changes in reversed speech; both these results argue against explanation of the native-language voice discrimination in terms of acoustic properties of the stimuli. The ability to identify talkers is, like many other perceptual abilities, strongly influenced by early life experience.

Abstract

Every language manifests casual speech processes, and hence every second language too. This study examined how listeners deal with second-language casual speech processes, as a function of the processes in their native language. We compared a match case, where a second-language process t/-reduction) is also operative in native speech, with a mismatch case, where a second-language process (/r/-insertion) is absent from native speech. In each case native and non-native listeners judged stimuli in which a given phoneme (in sentence context) varied along a continuum from absent to present. Second-language listeners in general mimicked native performance in the match case, but deviated significantly from native performance in the mismatch case. Together these results make it clear that the mapping from first to second language is as important in the interpretation of casual speech processes as in other dimensions of speech perception. Unfamiliar casual speech processes are difficult to adapt to in a second language. Casual speech processes that are already familiar from native speech, however, are easy to adapt to; indeed, our results even suggest that it is possible for subtle difference in their occurrence patterns across the two languages to be detected,and to be accommodated to in second-language listening

Abstract

In sequences such as law and order, speakers of British English often insert /r/ between law and and. Acoustic analyses revealed such “intrusive” /r/ to be significantly shorter than canonical /r/. In a 2AFC experiment, native listeners heard British English sentences in which /r/ duration was manipulated across a word boundary [e.g., saw (r)ice], and orthographic and semantic factors were varied. These listeners responded categorically on the basis of acoustic evidence for /r/ alone, reporting ice after short /r/s, rice after long /r/s; orthographic and semantic factors had no effect. Dutch listeners proficient in English who heard the same materials relied less on durational cues than the native listeners, and were affected by both orthography and semantic bias. American English listeners produced intermediate responses to the same materials, being sensitive to duration (less so than native, more so than Dutch listeners), and to orthography (less so than the Dutch), but insensitive to the semantic manipulation. Listeners from language communities without common use of intrusive /r/ may thus interpret intrusive /r/ as canonical /r/, with a language difference increasing this propensity more than a dialect difference. Native listeners, however, efficiently distinguish intrusive from canonical /r/ by exploiting the relevant acoustic variation.

Abstract

Languages differ in the constitution of their phonemic repertoire and in the relative distinctiveness of phonemes within the repertoire. In the present study, we asked whether such differences constrain spoken-word recognition, via two word reconstruction experiments, in which listeners turned non-words into real words by changing single sounds. The experiments were carried out in Dutch (which has a relatively balanced vowel-consonant ratio and many similar vowels) and in Spanish (which has many more consonants than vowels and high distinctiveness among the vowels). Both Dutch and Spanish listeners responded significantly faster and more accurately when required to change vowels as opposed to consonants; when allowed to change any phoneme, they more often altered vowels than consonants. Vowel information thus appears to constrain lexical selection less tightly (allow more potential candidates) than does consonant information, independent of language-specific phoneme repertoire and of relative distinctiveness of vowels.

Abstract

Spraak is continu, er zijn geen betrouwbare signalen waardoor de luisteraar weet waar het ene woord eindigt en het volgende begint. Voor volwassen luisteraars is het segmenteren van gesproken taal in afzonderlijke woorden dus niet onproblematisch, maar voor een kind dat nog geen woordenschat bezit, vormt de continuïteit van spraak een nog grotere uitdaging. Desalniettemin produceren de meeste kinderen hun eerste herkenbare woorden rond het begin van het tweede levensjaar. Aan deze vroege spraakproducties gaat een formidabele perceptuele prestatie vooraf. Tijdens het eerste levensjaar - met name gedurende de tweede helft - ontwikkelt de spraakperceptie zich van een algemeen fonetisch discriminatievermogen tot een selectieve gevoeligheid voor de fonologische contrasten die in de moedertaal voorkomen. Recent onderzoek heeft verder aangetoond dat kinderen, lang voordat ze ook maar een enkel woord kunnen zeggen, in staat zijn woorden die kenmerkend zijn voor hun moedertaal te onderscheiden van woorden die dat niet zijn. Bovendien kunnen ze woorden die eerst in isolatie werden aangeboden herkennen in een continue spraakcontext. Het dagelijkse taalaanbod aan een kind van deze leeftijd maakt het in zekere zin niet gemakkelijk, bijvoorbeeld doordat de meeste woorden niet in isolatie voorkomen. Toch wordt het kind ook wel houvast geboden, onder andere doordat het woordgebruik beperkt is.

Abstract

Dutch-learning and English-learning 9-month-olds were tested, using the Headturn Preference Procedure, for their ability to segment Dutch words with strong/weak stress patterns from fluent Dutch speech. This prosodic pattern is highly typical for words of both languages. The infants were familiarized with pairs of words and then tested on four passages, two that included the familiarized words and two that did not. Both the Dutch- and the English-learning infants gave evidence of segmenting the targets from the passages, to an equivalent degree. Thus, English-learning infants are able to extract words from fluent speech in a language that is phonetically different from English. We discuss the possibility that this cross-language segmentation ability is aided by the similarity of the typical rhythmic structure of Dutch and English words.

Abstract

The central thesis of the target article was that feedback is never necessary in spoken word recognition. The commentaries present no new data and no new theoretical arguments which lead us to revise this position. In this response we begin by clarifying some terminological issues which have lead to a number of significant misunderstandings. We provide some new arguments to support our case that the feedforward model Merge is indeed more parsimonious than the interactive alternatives, and that it provides a more convincing account of the data than alternative models. Finally, we extend the arguments to deal with new issues raised by the commentators such as infant speech perception and neural architecture.

Abstract

Top-down feedback does not benefit speech recognition; on the contrary, it can hinder it. No experimental data imply that feedback loops are required for speech recognition. Feedback is accordingly unnecessary and spoken word recognition is modular. To defend this thesis, we analyse lexical involvement in phonemic decision making. TRACE (McClelland & Elman 1986), a model with feedback from the lexicon to prelexical processes, is unable to account for all the available data on phonemic decision making. The modular Race model (Cutler & Norris 1979) is likewise challenged by some recent results, however. We therefore present a new modular model of phonemic decision making, the Merge model. In Merge, information flows from prelexical processes to the lexicon without feedback. Because phonemic decisions are based on the merging of prelexical and lexical information, Merge correctly predicts lexical involvement in phonemic decisions in both words and nonwords. Computer simulations show how Merge is able to account for the data through a process of competition between lexical hypotheses. We discuss the issue of feedback in other areas of language processing and conclude that modular models are particularly well suited to the problems and constraints of speech recognition.

Abstract

In three experiments, the processing of lexical tone in Cantonese was examined. Cantonese listeners more often accepted a nonword as a word when the only difference between the nonword and the word was in tone, especially when the F0 onset difference between correct and erroneous tone was small. Same–different judgments by these listeners were also slower and less accurate when the only difference between two syllables was in tone, and this was true whether the F0 onset difference between the two tones was large or small. Listeners with no knowledge of Cantonese produced essentially the same same-different judgment pattern as that produced by the native listeners, suggesting that the results display the effects of simple perceptual processing rather than of linguistic knowledge. It is argued that the processing of lexical tone distinctions may be slowed, relative to the processing of segmental distinctions, and that, in speeded-response tasks, tone is thus more likely to be misprocessed than is segmental structure.

Abstract

Research on the exploitation of prosodic information in the recognition of spoken language is reviewed. The research falls into three main areas: the use of prosody in the recognition of spoken words, in which most attention has been paid to the question of whether the prosodic structure of a word plays a role in initial contact with stored lexical representations; the use of prosody in the computation of syntactic structure, in which the resolution of global and local ambiguities has formed the central focus; and the role of prosody in the processing of discourse structure, in which there has been a preponderance of work on the contribution of accentuation and deaccentuation to integration of concepts with an existing discourse model. The review reveals that in each area progress has been made towards new conceptions of prosody's role in processing, and in particular this has involved abandonment of previously held deterministic views of the relationship between prosodic structure and other aspects of linguistic structure

Abstract

Psycholinguists strive to construct a model of human language processing in general. But this does not imply that they should confine their research to universal aspects of linguistic structure, and avoid research on language-specific phenomena. First, even universal characteristics of language structure can only be accurately observed cross-linguistically. This point is illustrated here by research on the role of the syllable in spoken-word recognition, on the perceptual processing of vowels versus consonants, and on the contribution of phonetic assimilation phonemena to phoneme identification. In each case, it is only by looking at the pattern of effects across languages that it is possible to understand the general principle. Second, language-specific processing can certainly shed light on the universal model of language comprehension. This second point is illustrated by studies of the exploitation of vowel harmony in the lexical segmentation of Finnish, of the recognition of Dutch words with and without vowel epenthesis, and of the contribution of different kinds of lexical prosodic structure (tone, pitch accent, stress) to the initial activation of candidate words in lexical access. In each case, aspects of the universal processing model are revealed by analysis of these language-specific effects. In short, the study of spoken-language processing by human listeners requires cross-linguistic comparison.

Abstract

We propose that word recognition in continuous speech is subject to constraints on what may constitute a viable word of the language. This Possible-Word Constraint (PWC) reduces activation of candidate words if their recognition would imply word status for adjacent input which could not be a word - for instance, a single consonant. In two word-spotting experiments, listeners found it much harder to detectapple,for example, infapple(where [f] alone would be an impossible word), than invuffapple(wherevuffcould be a word of English). We demonstrate that the PWC can readily be implemented in a competition-based model of continuous speech recognition, as a constraint on the process of competition between candidate words; where a stretch of speech between a candidate word and a (known or likely) word boundary is not a possible word, activation of the candidate word is reduced. This implementation accurately simulates both the present results and data from a range of earlier studies of speech segmentation.

Abstract

Finnish vowel harmony rules require that if the vowel in the first syllable of a word belongs to one of two vowel sets, then all subsequent vowels in that word must belong either to the same set or to a neutral set. A harmony mismatch between two syllables containing vowels from the opposing sets thus signals a likely word boundary. We report five experiments showing that Finnish listeners can exploit this information in an on-line speech segmentation task. Listeners found it easier to detect words likehymyat the end of the nonsense stringpuhymy(where there is a harmony mismatch between the first two syllables) than in the stringpyhymy(where there is no mismatch). There was no such effect, however, when the target words appeared at the beginning of the nonsense string (e.g.,hymypuvshymypy). Stronger harmony effects were found for targets containing front harmony vowels (e.g.,hymy) than for targets containing back harmony vowels (e.g.,paloinkypaloandkupalo). The same pattern of results appeared whether target position within the string was predictable or unpredictable. Harmony mismatch thus appears to provide a useful segmentation cue for the detection of word onsets in Finnish speech.

Abstract

One of a listener’s major tasks in understanding continuous speech in segmenting the speech signal into separate words. When listening conditions are difficult, speakers can help listeners by deliberately clear speech. We found that speakers do indeed attempt to makr word boundaries; moreover, they differentiate between word boundaries in a way which suggest they are sensitive to listener needs. Application of heuristic segmentation strategies makes word boundaries before strong syllables easiest for listeners to perceive; but under difficult listening conditions speakers pay more attention to marking word boundaries before weak syllables, i.e. they mark those boundaries which are otherwise particularly hard to perceive.

Abstract

It is a widely held belief that women talk more than men; but experimental evidence has suggested that this belief is mistaken. The present study investigated whether listener bias contributes to this mistake. Dialogues were recorded in mixed-sex and single-sex versions, and male and female listeners judged the proportions of talk contributed to the dialogues by each participant. Female contributions to mixed-sex dialogues were rated as greater than male contributions by both male and female listeners. Female contributions were more likely to be overestimated when they were speaking a dialogue part perceived as probably female than when they were speaking a dialogue part perceived as probably male. It is suggested that the misestimates are due to a complex of factors that may involve both perceptual effects such as misjudgment of rates of speech and sociological effects such as attitudes to social roles and perception of power relations.

Abstract

The roles which word class (open/closed) and sentential stress play in the sentence comprehension processes of both agrammatic (Broca's) aphasics and normal listeners were examined with a word monitoring task. Overall, normal listeners responded more quickly to stressed than to unstressed items, but showed no effect of word class. Aphasics also responded more quickly to stressed than to unstressed materials, but, unlike the normals, responded faster to open than to closed class words regardless of their stress. The results are interpreted as support for the theory that Broca's aphasics lack the functional underlying open/closed class word distinction used in word recognition by normal listeners.

Abstract

The order of some conjoined words is rigidly fixed (e.g. dribs and drabs/*drabs and dribs). Both phonetic and semantic factors can play a role in determining the fixed order. An experiment was conducted to test whether listerners’ reaction times for monitoring a predetermined phoneme are influenced by phonetic constraints on ordering. Two such constraints were investigated: monosyllable-bissyllable and high-low vowel sequences. In English, conjoined words occur in such sequences with much greater frequency than their converses, other factors being equal. Reaction times were significantly shorter for phoneme monitoring in monosyllable-bisyllable sequences than in bisyllable- monosyllable sequences. However, reaction times were not significantly different for high-low vs. low-high vowel sequences.