Native Dutch Listeners Research Articles

Dutch speech intelligibility in bilingual Turkish-Dutch children in Flanders

AbstractThis study examines the Dutch intelligibility of a group of monolingual Dutch and bilingual Turkish-Dutch preschool children in Flanders, as rated by native Dutch listeners and measured by a Dutch intelligibility test. The intelligibility of the bilingual children is compared to that of the monolingual Dutch children, in order to examine whether age and/or task effects are similar or different in the two groups. The results revealed that intelligibility was affected by age, but showed no significant interaction between age and group. However, we found a significant interaction between age and task: children’s intelligibility increased with age for a word production as well as a sentence production task, but much more so for the latter than for the former. We discuss the results in relation to the children’s developing phonological systems, the age of exposure to Dutch and the nature of the test.

The effect of intermittent noise on lexically-guided perceptual learning in native and non-native listening

There is ample evidence that both native and non-native listeners deal with speech variation by quickly tuning into a speaker and adjusting their phonetic categories according to the speaker’s ambiguous pronunciation. This process is called lexically-guided perceptual learning. Moreover, the presence of noise in the speech signal has previously been shown to change the word competition process by increasing the number of candidate words competing for recognition and slowing down the recognition process. Given that reliable lexical information should be available quickly to induce lexically-guided perceptual learning and that word recognition is slowed down in the presence of noise, and especially so for non-native listeners, the present study investigated whether noise interferes with lexically-guided perceptual learning in native and non-native listening. Native English and Dutch listeners were exposed to a story in English in clean speech or with stretches of noise. All the /l/ and /ɹ/ sounds in the story were replaced with an ambiguous sound half-way between /l/ and /ɹ/. Although noise altered the pattern of responses for the non-native listeners in a subsequent phonetic categorization task, both native and non-native listeners demonstrated lexically-guided perceptual learning in both clean and noisy listening conditions. We argue that the robustness of perceptual learning in the presence of intermittent noise for both native and non-native listeners is additional evidence for the remarkable flexibility of native and non-native perceptual systems even in adverse listening conditions.

(Not so) Great Expectations: Listening to Foreign-Accented Speech Reduces the Brain's Anticipatory Processes.

This study examines the effect of foreign-accented speech on the predictive ability of our brain. Listeners actively anticipate upcoming linguistic information in the speech signal so as to facilitate and reduce processing load. However, it is unclear whether or not listeners also do this when they are exposed to speech from non-native speakers. In the present study, we exposed native Dutch listeners to sentences produced by native and non-native speakers while measuring their brain activity using electroencephalography. We found that listeners’ brain activity differed depending on whether they listened to native or non-native speech. However, participants’ overall performance as measured by word recall rate was unaffected. We discussed the results in relation to previous findings as well as the automaticity of anticipation.

Matching Acoustical Properties and Native Perceptual Assessments of L2 Speech

AbstractThis article analyses the acoustical properties of Dutch vowels produced by adult Spanish learners and investigates how these vowels are perceived by non-expert native Dutch listeners. Statistical vowel classifications obtained from the acoustical properties of the learner vowel realizations were compared to vowel classifications provided by native Dutch listeners. Both types of classifications were affected by the specific set of vowels included as stimuli, an effect caused by the large variability in Spanish learners’ vowel realizations. While there were matches between the two types of classifications, shifts were noted within and between production and perception, depending on the vowel and vowel features. We considered the variability between Spanish learners further by investigating individual patterns in the production and perception data, and linking these to the learners’ proficiency level and multilingual background. We conclude that integrating production and perception data provides valuable insights into the role of different features in adult L2 learning, and how their properties actively interact in the way L2 speech is perceived. A second conclusion is that adaptive mechanisms, signalled by boundary shifts and useful in coping with variability of non-native vowel stimuli, play a role in both statistical vowel classifications (production) and human vowel recognition (perception).

The direct and indirect effects of the phonotactic constraints in the listener’s native language on the comprehension of reduced and unreduced word pronunciation variants in a foreign language

This study investigates how the comprehension of casual speech in foreign languages is affected by the phonotactic constraints in the listener’s native language. Non-native listeners of English with different native languages heard short English phrases produced by native speakers of English or Spanish and they indicated whether these phrases included can or can’t. Native Mandarin listeners especially tended to interpret can’t as can. We interpret this result as a direct effect of the ban on word-final /nt/ in Mandarin. Both the native Mandarin and the native Spanish listeners did not take full advantage of the subsegmental information in the speech signal cueing reduced can’t. This finding is probably an indirect effect of the phonotactic constraints in their native languages: these listeners have difficulties interpreting the subsegmental cues because these cues do not occur or have different functions in their native languages. Dutch resembles English in the phonotactic constraints relevant to the comprehension of can’t, and native Dutch listeners showed similar patterns in their comprehension of native and non-native English to native English listeners. This result supports our conclusion that the major patterns in the comprehension results are driven by the phonotactic constraints in the listeners’ native languages.

The developmental trajectories of attention distribution and segment-tone integration in Dutch learners of Mandarin tones

This study investigates how beginner and advanced Dutch learners of Mandarin process tonal information. An ABX task was adopted to investigate phonological discrimination of Mandarin tones and segment-tone integration in Dutch learners of Mandarin, with both native Mandarin and Dutch speakers (without tonal learning experience) as control groups. Results showed a developmental path in lexical tone processing. The beginner learners could not process tonal contrast adequately at the phonological level, and they processed segmental and tonal information separately, like native Dutch listeners without Mandarin experience. The advanced learners showed a good phonological discrimination of tonal contrasts. They showed a more native-like pattern in distributing their attention between segmental and tonal information, and they processed the two dimensions in an integrated manner, similar to native Mandarin listeners. This suggests that the acquisition of new tonal categories in L2 involves a redistribution of attention along perceptual dimensions and the development of segment-tone integration.

Speaker and Accent Variation Are Handled Differently: Evidence in Native and Non-Native Listeners.

Listeners are able to cope with between-speaker variability in speech that stems from anatomical sources (i.e. individual and sex differences in vocal tract size) and sociolinguistic sources (i.e. accents). We hypothesized that listeners adapt to these two types of variation differently because prior work indicates that adapting to speaker/sex variability may occur pre-lexically while adapting to accent variability may require learning from attention to explicit cues (i.e. feedback). In Experiment 1, we tested our hypothesis by training native Dutch listeners and Australian-English (AusE) listeners without any experience with Dutch or Flemish to discriminate between the Dutch vowels /I/ and /ε/ from a single speaker. We then tested their ability to classify /I/ and /ε/ vowels of a novel Dutch speaker (i.e. speaker or sex change only), or vowels of a novel Flemish speaker (i.e. speaker or sex change plus accent change). We found that both Dutch and AusE listeners could successfully categorize vowels if the change involved a speaker/sex change, but not if the change involved an accent change. When AusE listeners were given feedback on their categorization responses to the novel speaker in Experiment 2, they were able to successfully categorize vowels involving an accent change. These results suggest that adapting to accents may be a two-step process, whereby the first step involves adapting to speaker differences at a pre-lexical level, and the second step involves adapting to accent differences at a contextual level, where listeners have access to word meaning or are given feedback that allows them to appropriately adjust their perceptual category boundaries.

Putting things in new places: Linguistic experience modulates the predictive power of placement verb semantics

Abstract A central question regarding predictive language processing concerns the extent to which linguistic experience modulates the process. We approached this question by investigating sentence processing in advanced second language (L2) users with different native language (L1) backgrounds. Using a visual world eye tracking paradigm, we investigated to what extent L1 and L2 participants showed anticipatory eye movements to objects while listening to Dutch placement event descriptions. L2 groups differed in the degree of similarity between Dutch and their L1 with respect to placement verb semantics: German, like Dutch, specifies object position in placement verbs (put.STAND vs. put.LIE), whereas English and French typically leave position underspecified (put). Results showed that German L2 listeners, like native Dutch listeners, anticipate objects that match the verbally encoded position immediately upon encountering the verb. French/English L2 participants, however, did not show any prediction effects, despite proper understanding of Dutch placement verbs. Our findings suggest that prior experience with a specific semantic contrast in one’s L1 facilitates prediction in L2, and hence adds to the evidence that linguistic experience modulates predictive sentence processing.

Cross-linguistic perception of Mandarin tone sandhi

In the current study, we examined what forms the phonological knowledge of T3 sandhi among native Mandarin listeners and we ask the question whether there are cognitively based perceptual constraints that relate to T3 sandhi. In Mandarin Chinese, T3 sandhi restricts the co-occurrence of low tones (T3), and neutralizes the rising tone (T2) and T3 when followed by another T3. We tested native Mandarin Chinese listeners and Dutch listeners on bisyllabic tone discrimination tasks. We found that the phonological knowledge of native listeners involves the neutralization between T2T3 and underlying T3T3 sequences, rather than perceiving a boundary between consecutive T3s. Dutch listener, without the phonological knowledge of Chinese tones, also perceive T2T3 as most similar to the underlying T3T3 sequence. Such cross-linguistic consistency in perception suggests a common functional basis, where memory limitation may play a role. Listeners may attend more to the offset of an incoming tone, and as T2T3 and T3T3 share the same offset, they tend to be misperceived as identical. Regardless of the cross-linguistic consistency in perception, the misperception between T2T3 and underlying T3T3 is more pronounced among Mandarin listeners, showing that phonological knowledge shapes perception in return.

Individual aptitude in Mandarin lexical tone perception predicts effectiveness of high-variability training.

Although the high-variability training method can enhance learning of non-native speech categories, this can depend on individuals’ aptitude. The current study asked how general the effects of perceptual aptitude are by testing whether they occur with training materials spoken by native speakers and whether they depend on the nature of the to-be-learned material. Forty-five native Dutch listeners took part in a 5-day training procedure in which they identified bisyllabic Mandarin pseudowords (e.g., asa) pronounced with different lexical tone combinations. The training materials were presented to different groups of listeners at three levels of variability: low (many repetitions of a limited set of words recorded by a single speaker), medium (fewer repetitions of a more variable set of words recorded by three speakers), and high (similar to medium but with five speakers). Overall, variability did not influence learning performance, but this was due to an interaction with individuals’ perceptual aptitude: increasing variability hindered improvements in performance for low-aptitude perceivers while it helped improvements in performance for high-aptitude perceivers. These results show that the previously observed interaction between individuals’ aptitude and effects of degree of variability extends to natural tokens of Mandarin speech. This interaction was not found, however, in a closely matched study in which native Dutch listeners were trained on the Japanese geminate/singleton consonant contrast. This may indicate that the effectiveness of high-variability training depends not only on individuals’ aptitude in speech perception but also on the nature of the categories being acquired.

Tolerance for inconsistency in foreign-accented speech

Are listeners able to adapt to a foreign-accented speaker who has, as is often the case, an inconsistent accent? Two groups of native Dutch listeners participated in a cross-modal priming experiment, either in a consistent-accent condition (German-accented items only) or in an inconsistent-accent condition (German-accented and nativelike pronunciations intermixed). The experimental words were identical for both groups (words with vowel substitutions characteristic of German-accented speech); additional contextual words differed in accentedness (German-accented or nativelike words). All items were spoken by the same speaker: a German native who could produce the accented forms but could also pass for a Dutch native speaker. Listeners in the consistent-accent group were able to adapt quickly to the speaker (i.e., showed facilitatory priming for words with vocalic substitutions). Listeners in the inconsistent-accent condition showed adaptation to words with vocalic substitutions only in the second half of the experiment. These results indicate that adaptation to foreign-accented speech is rapid. Accent inconsistency slows listeners down initially, but a short period of additional exposure is enough for them to adapt to the speaker. Listeners can therefore tolerate inconsistency in foreign-accented speech.

Foreign accent strength and listener familiarity with an accent codetermine speed of perceptual adaptation

We investigated how the strength of a foreign accent and varying types of experience with foreign-accented speech influence the recognition of accented words. In Experiment 1, native Dutch listeners with limited or extensive prior experience with German-accented Dutch completed a cross-modal priming experiment with strongly, medium, and weakly accented words. Participants with limited experience were primed by the medium and weakly accented words, but not by the strongly accented words. Participants with extensive experience were primed by all accent types. In Experiments 2 and 3, Dutch listeners with limited experience listened to a short story before doing the cross-modal priming task. In Experiment 2, the story was spoken by the priming task speaker and either contained strongly accented words or did not. Strongly accented exposure led to immediate priming by novel strongly accented words, while exposure to the speaker without strongly accented tokens led to priming only in the experiment's second half. In Experiment 3, listeners listened to the story with strongly accented words spoken by a different German-accented speaker. Listeners were primed by the strongly accented words, but again only in the experiment's second half. Together, these results show that adaptation to foreign-accented speech is rapid but depends on accent strength and on listener familiarity with those strongly accented words.

Effects of native language on perceptual sensitivity to phonetic cues

The present study used electrophysiological and behavioral measures to investigate the perception of an English stop consonant contrast by native English listeners and by native Dutch listeners who were highly proficient in English. A /ba/-/pa/ continuum was created from a naturally produced /pa/ token by removing successive periods of aspiration, thus reducing the voice onset time. Although aspiration is a relevant cue for distinguishing voiced and unvoiced labial stop consonants (/b/ and /p/) in English, prevoicing is the primary cue used to distinguish between these categories in Dutch. In the electrophysiological experiment, participants listened to oddball sequences containing the standard /pa/ stimulus and one of three deviant stimuli while the mismatch-negativity response was measured. Participants then completed an identification task on the same stimuli. The results showed that native English participants were more sensitive to reductions in aspiration than native Dutch participants, as indicated by shifts in the category boundary, by differing within-group patterns of mismatch-negativity responses, and by larger mean evoked potential amplitudes in the native English group for two of the three deviant stimuli. This between-group difference in the sensorineural processing of aspiration cues indicates that native language experience alters the way in which the acoustic features of speech are processed in the auditory brain, even following extensive second-language training.

The Role of Native-Language Knowledge in the Perception of Casual Speech in a Second Language

Casual speech processes, such as /t/-reduction, make word recognition harder. Additionally, word recognition is also harder in a second language (L2). Combining these challenges, we investigated whether L2 learners have recourse to knowledge from their native language (L1) when dealing with casual speech processes in their L2. In three experiments, production and perception of /t/-reduction was investigated. An initial production experiment showed that /t/-reduction occurred in both languages and patterned similarly in proper nouns but differed when /t/ was a verbal inflection. Two perception experiments compared the performance of German learners of Dutch with that of native speakers for nouns and verbs. Mirroring the production patterns, German learners’ performance strongly resembled that of native Dutch listeners when the reduced /t/ was part of a word stem, but deviated where /t/ was a verbal inflection. These results suggest that a casual speech process in a second language is problematic for learners when the process is not known from the leaner’s native language, similar to what has been observed for phoneme contrasts.

Adapting to foreign-accented speech: The role of delay in testing

Understanding speech usually seems easy, but it can become noticeably harder when the speaker has a foreign accent. This is because foreign accents add considerable variation to speech. Research on foreign-accented speech shows that participants are able to adapt quickly to this type of variation. Less is known, however, about longer-term maintenance of adaptation. The current study focused on long-term adaptation by exposing native listeners to foreign-accented speech on Day 1, and testing them on comprehension of the accent one day later. Comprehension was thus not tested immediately, but only after a 24 h period. On Day 1, native Dutch listeners listened to the speech of a Hebrew learner of Dutch while performing a phoneme monitoring task that did not depend on the talker's accent. In particular, shortening of the long vowel /i/ into /I/ (e.g., lief [li:f], 'sweet', pronounced as [lIf]) was examined. These mispronunciations did not create lexical ambiguities in Dutch. On Day 2, listeners participated in a cross-modal priming task to test their comprehension of the accent. The results will be contrasted with results from an experiment without delayed testing and related to accounts of how listeners maintain adaptation to foreign-accented speech.

Native, non-native and L2 perceptual cue weighting for Dutch vowels: The case of Dutch, German, and Spanish listeners

Previous research has demonstrated that learners of English with different L1 backgrounds diverge from native speakers in their use of acoustic cues for the perception and production of vowel contrasts. This study investigated the use of two cues, i.e. , vowel spectrum and duration, for the categorization of the Dutch /aː/-/ɑ/ contrast in three groups of listeners: L1-Dutch, L1-Spanish L2-Dutch, and L1-German listeners. Three aspects of vowel contrast perception were tested: the categorical nature of the listeners’ perceptual boundary, their cue weighting, and their use of the individual cues. Experience with the Dutch language played a role in the ability to perceptually distinguish the two vowel categories: Native Dutch listeners and Spanish learners of Dutch could categorize prototypical tokens of Dutch /aː/ and /ɑ/ more reliably than L1-German listeners without experience with the Dutch language. Native Dutch listeners had the most sharply defined boundary between the two categories. The results also show that language background strongly affects vowel perception: both L1-Dutch and L1-German listeners weight vowel spectrum heavier than vowel duration, whereas L1-Spanish L2-Dutch listeners favour vowel duration. L1-German listeners’ cue weighting can be explained in terms of the cross-linguistic comparison between German and Dutch vowels. L1-Spanish L2-Dutch listeners’ results have implications for theories of second language perception.

Native-language influence on phonetic perception in Dutch–English bilinguals

We examined how native-language experience influences processing a second language, focusing on how native Dutch listeners who learned English as a second language perceive the English voiceless consonant /p/. Previous research [J. E. Flege and W. Eefting, Speech Commun. 6, 185–202 (1987)] shows that the voiced–voiceless boundary for an (English-based) voice-onset-time (VOT) series is located at a shorter VOT for such bilingual listeners than for native English listeners, consistent with the fact that voiceless stops are produced with shorter VOTs in Dutch than in English. We asked whether such bilinguals also differ from native English listeners in which stimuli throughout the series are perceived as reasonable exemplars of /p/. Native English listeners and native Dutch listeners were tested on a three-choice identification task with an (English-based) extended VOT series that ranged from /ba/ to /pa/ to an ‘‘unnatural’’ exaggerated /pa/, labeled */pa/. Both the /b/-/p/ and /p/-*/p/ boundaries were located at shorter VOTs for the native Dutch than the native English listeners, indicating that Dutch native-language experience influenced the entire range of VOTs perceived as reasonable exemplars of the /p/ category. Thus native-language experience has a comprehensive influence on the mapping from acoustic signal to phonetic category. [Work supported by NIH/NIDCD.]

Intelligibility of native and non-native Dutch speech

The intelligibility of speech is known to be lower if the speaker is non-native instead of native for the given language. This study is aimed at quantifying the overall degradation due to limitations of non-native speakers of Dutch, specifically of Dutch-speaking Americans who have lived in the Netherlands 1–3 years. Experiments were focused on phoneme intelligibility and sentence intelligibility, using additive noise as a means of degrading the intelligibility of speech utterances for test purposes. The overall difference in sentence intelligibility between native Dutch speakers and American speakers of Dutch, using native Dutch listeners, was found to correspond to a difference in speech-to-noise ratio (SNR) of approximately 3 dB. The main segmental contribution to the degradation of speech intelligibility by introducing non-native speakers and/or listeners is the confusion of vowels, especially those that do not occur in American English. Vowels that are difficult for second-language speakers to produce are also difficult for second-language listeners to classify; such vowels attract false recognition, reducing the overall recognition rate for all vowels.

The effect of a non-native accent in Dutch on speech intelligibility

It is well known that second-language talkers are usually less intelligible than native talkers, especially under adverse listening conditions. Background noise tends to influence the intelligibility of foreign accented speech more profoundly than unaccented speech. In order to quantify this effect, speech reception threshold (SRT) experiments were carried out using Dutch speech by American, German, Polish, Chinese and (native) Dutch talkers (15 speakers, 3 talkers per language background). The experience with the Dutch language varied between talkers from 3 months to 28 years. Ten Dutch university students participated as listeners. In order to obtain 50% sentence intelligibility, non-native talkers were found to require a 0–3-dB better speech-to-noise ratio than native talkers do. A significant correlation between self-reported proficiency and SRT-score was observed (R=0.78). Also, an objective estimate of the degree of foreign accent of the individual speakers was obtained by means of a pairwise comparison experiment, in which 19 native Dutch listeners participated. The accent ratings which were obtained (after Thurstone normalization) were also significantly correlated with the SRT-scores (R=0.85). The conclusion may be drawn that the effect of noise on the intelligibility of foreign accented speech can be predicted quantitatively from easily obtained measures of perceived foreign accent.

Help or hindrance: how violation of different assimilation rules affects spoken-language processing.

Four phoneme-detection studies tested the conclusion from recent research that spoken-language processing is inhibited by violation of obligatory assimilation processes in the listeners' native language. In Experiment 1, native listeners of German detected a target fricative in monosyllabic Dutch nonwords, half of which violated progressive German fricative place assimilation. In contrast to the earlier findings, listeners detected the fricative more quickly when assimilation was violated than when no violation occurred. This difference was not due to purely acoustic factors, since in Experiment 2 native Dutch listeners, presented with the same materials, showed no such effect. In Experiment 3, German listeners again detected the fricative more quickly when violation occurred in both monosyllabic and bisyllabic native nonwords, further ruling out explanations based on non-native input or on syllable structure. Finally Experiment 4 tested whether the direction in which the rule operates (progressive or regressive) controls the direction of the effect on phoneme detection responses. When regressive German place assimilation for nasals was violated, German listeners detected stops more slowly, exactly as had been observed in previous studies of regressive assimilation. It is argued that a combination of low expectations in progressive assimilation and novel popout causes facilitation of processing, whereas not fulfilling high expectations in regressive assimilation causes inhibition.