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  • Rodd, J., Bosker, H. R., Ernestus, M., Alday, P. M., Meyer, A. S., & Ten Bosch, L. (2020). Control of speaking rate is achieved by switching between qualitatively distinct cognitive ‘gaits’: Evidence from simulation. Psychological Review, 127(2), 281-304. doi:10.1037/rev0000172.

    Abstract

    That speakers can vary their speaking rate is evident, but how they accomplish this has hardly been studied. Consider this analogy: When walking, speed can be continuously increased, within limits, but to speed up further, humans must run. Are there multiple qualitatively distinct speech “gaits” that resemble walking and running? Or is control achieved by continuous modulation of a single gait? This study investigates these possibilities through simulations of a new connectionist computational model of the cognitive process of speech production, EPONA, that borrows from Dell, Burger, and Svec’s (1997) model. The model has parameters that can be adjusted to fit the temporal characteristics of speech at different speaking rates. We trained the model on a corpus of disyllabic Dutch words produced at different speaking rates. During training, different clusters of parameter values (regimes) were identified for different speaking rates. In a 1-gait system, the regimes used to achieve fast and slow speech are qualitatively similar, but quantitatively different. In a multiple gait system, there is no linear relationship between the parameter settings associated with each gait, resulting in an abrupt shift in parameter values to move from speaking slowly to speaking fast. After training, the model achieved good fits in all three speaking rates. The parameter settings associated with each speaking rate were not linearly related, suggesting the presence of cognitive gaits. Thus, we provide the first computationally explicit account of the ability to modulate the speech production system to achieve different speaking styles.

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  • Ernestus, M., Dikmans, M., & Giezenaar, G. (2017). Advanced second language learners experience difficulties processing reduced word pronunciation variants. Dutch Journal of Applied Linguistics, 6(1), 1-20. doi:10.1075/dujal.6.1.01ern.

    Abstract

    Words are often pronounced with fewer segments in casual conversations than in formal speech. Previous research has shown that foreign language learners and beginning second language learners experience problems processing reduced speech. We examined whether this also holds for advanced second language learners. We designed a dictation task in Dutch consisting of sentences spliced from casual conversations and an unreduced counterpart of this task, with the same sentences carefully articulated by the same speaker. Advanced second language learners of Dutch produced substantially more transcription errors for the reduced than for the unreduced sentences. These errors made the sentences incomprehensible or led to non-intended meanings. The learners often did not rely on the semantic and syntactic information in the sentence or on the subsegmental cues to overcome the reductions. Hence, advanced second language learners also appear to suffer from the reduced pronunciation variants of words that are abundant in everyday conversations
  • Ernestus, M., Kouwenhoven, H., & Van Mulken, M. (2017). 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. Journal of Phonetics, 62, 50-64. doi:10.1016/j.wocn.2017.02.003.

    Abstract

    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.
  • Ten Bosch, L., Boves, L., & Ernestus, M. (2017). The recognition of compounds: A computational account. In Proceedings of Interspeech 2017 (pp. 1158-1162). doi:10.21437/Interspeech.2017-1048.

    Abstract

    This paper investigates the processes in comprehending spoken noun-noun compounds, using data from the BALDEY database. BALDEY contains lexicality judgments and reaction times (RTs) for Dutch stimuli for which also linguistic information is included. Two different approaches are combined. The first is based on regression by Dynamic Survival Analysis, which models decisions and RTs as a consequence of the fact that a cumulative density function exceeds some threshold. The parameters of that function are estimated from the observed RT data. The second approach is based on DIANA, a process-oriented computational model of human word comprehension, which simulates the comprehension process with the acoustic stimulus as input. DIANA gives the identity and the number of the word candidates that are activated at each 10 ms time step.

    Both approaches show how the processes involved in comprehending compounds change during a stimulus. Survival Analysis shows that the impact of word duration varies during the course of a stimulus. The density of word and non-word hypotheses in DIANA shows a corresponding pattern with different regimes. We show how the approaches complement each other, and discuss additional ways in which data and process models can be combined.
  • De Vaan, L., Van Krieken, K., Van den Bosch, W., Schreuder, R., & Ernestus, M. (2017). The traces that novel morphologically complex words leave in memory are abstract in nature. The Mental Lexicon, 12(2), 181-218. doi:10.1075/ml.16006.vaa.

    Abstract

    Previous work has shown that novel morphologically complex words (henceforth neologisms) leave traces in memory after just one encounter. This study addressed the question whether these traces are abstract in nature or exemplars. In three experiments, neologisms were either primed by themselves or by their stems. The primes occurred in the visual modality whereas the targets were presented in the auditory modality (Experiment 1) or vice versa (Experiments 2 and 3). The primes were presented in sentences in a selfpaced reading task (Experiment 1) or in stories in a listening comprehension task (Experiments 2 and 3). The targets were incorporated in lexical decision tasks, auditory or visual (Experiment 1 and Experiment 2, respectively), or in stories in a self-paced reading task (Experiment 3). The experimental part containing the targets immediately followed the familiarization phase with the primes (Experiment 1), or after a one week delay (Experiments 2 and 3). In all experiments, participants recognized neologisms faster if they had encountered them before (identity priming) than if the familiarization phase only contained the neologisms’ stems (stem priming). These results show that the priming effects are robust despite substantial differences between the primes and the targets. This suggests that the traces novel morphologically complex words leave in memory after just one encounter are abstract in nature.
  • Viebahn, M., Ernestus, M., & McQueen, J. M. (2017). Speaking style influences the brain’s electrophysiological response to grammatical errors in speech comprehension. Journal of Cognitive Neuroscience, 29(7), 1132-1146. doi:10.1162/jocn_a_01095.

    Abstract

    This electrophysiological study asked whether the brain processes grammatical gender
    violations in casual speech differently than in careful speech. Native speakers of Dutch were
    presented with utterances that contained adjective-noun pairs in which the adjective was either
    correctly inflected with a word-final schwa (e.g. een spannende roman “a suspenseful novel”) or
    incorrectly uninflected without that schwa (een spannend roman). Consistent with previous
    findings, the uninflected adjectives elicited an electrical brain response sensitive to syntactic
    violations when the talker was speaking in a careful manner. When the talker was speaking in a
    casual manner, this response was absent. A control condition showed electrophysiological responses
    for carefully as well as casually produced utterances with semantic anomalies, showing that
    listeners were able to understand the content of both types of utterance. The results suggest that
    listeners take information about the speaking style of a talker into account when processing the
    acoustic-phonetic information provided by the speech signal. Absent schwas in casual speech are
    effectively not grammatical gender violations. These changes in syntactic processing are evidence
    of contextually-driven neural flexibility.

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  • Braun, B., Dainora, A., & Ernestus, M. (2011). An unfamiliar intonation contour slows down online speech comprehension. Language and Cognitive Processes, 26(3), 350 -375. doi:10.1080/01690965.2010.492641.

    Abstract

    This study investigates whether listeners' familiarity with an intonation contour affects speech processing. In three experiments, Dutch participants heard Dutch sentences with normal intonation contours and with unfamiliar ones and performed word-monitoring, lexical decision, or semantic categorisation tasks (the latter two with cross-modal identity priming). The unfamiliar intonation contour slowed down participants on all tasks, which demonstrates that an unfamiliar intonation contour has a robust detrimental effect on speech processing. Since cross-modal identity priming with a lexical decision task taps into lexical access, this effect obtained in this task suggests that an unfamiliar intonation contour hinders lexical access. Furthermore, results from the semantic categorisation task show that the effect of an uncommon intonation contour is long-lasting and hinders subsequent processing. Hence, intonation not only contributes to utterance meaning (emotion, sentence type, and focus), but also affects crucial aspects of the speech comprehension process and is more important than previously thought.
  • Brenner, D., Warner, N., Ernestus, M., & Tucker, B. V. (2011). Parsing the ambiguity of casual speech: “He was like” or “He’s like”? [Abstract]. The Journal of the Acoustical Society of America, 129(4 Pt. 2), 2683.

    Abstract

    Paper presented at The 161th Meeting Acoustical Society of America, Seattle, Washington, 23-27 May 2011. Reduction in casual speech can create ambiguity, e.g., “he was” can sound like “he’s.” Before quotative “like” “so she’s/she was like…”, it was found that there is little accurate acoustic information about the distinction in the signal. This work examines what types of information acoustics of the target itself, speech rate, coarticulation, and syntax/semantics listeners use to recognize such reduced function words. We compare perception studies presenting the targets auditorily with varying amounts of context, presenting the context without the targets, and a visual study presenting context in written form. Given primarily discourse information visual or auditory context only, subjects are strongly biased toward past, reflecting the use of quotative “like” for reporting past speech. However, if the target itself is presented, the direction of bias reverses, indicating that listeners favor acoustic information within the target which is reduced, sounding like the shorter, present form over almost any other source of information. Furthermore, when the target is presented auditorily with surrounding context, the bias shifts slightly toward the direction shown in the orthographic or auditory-no-target experiments. Thus, listeners prioritize acoustic information within the target when present, even if that information is misleading, but they also take discourse information into account.
  • Bürki, A., Ernestus, M., Gendrot, C., Fougeron, C., & Frauenfelder, U. H. (2011). What affects the presence versus absence of schwa and its duration: A corpus analysis of French connected speech. Journal of the Acoustical Society of America, 130, 3980-3991. doi:10.1121/1.3658386.

    Abstract

    This study presents an analysis of over 4000 tokens of words produced as variants with and without schwa in a French corpus of radio-broadcasted speech. In order to determine which of the many variables mentioned in the literature influence variant choice, 17 predictors were tested in the same analysis. Only five of these variables appeared to condition variant choice. The question of the processing stage, or locus, of this alternation process is also addressed in a comparison of the variables that predict variant choice with the variables that predict the acoustic duration of schwa in variants with schwa. Only two variables predicting variant choice also predict schwa duration. The limited overlap between the predictors for variant choice and for schwa duration, combined with the nature of these variables, suggest that the variants without schwa do not result from a phonetic process of reduction; that is, they are not the endpoint of gradient schwa shortening. Rather, these variants are generated early in the production process, either during phonological encoding or word-form retrieval. These results, based on naturally produced speech, provide a useful complement to on-line production experiments using artificial speech tasks.
  • Ernestus, M., & Baayen, R. H. (2011). Corpora and exemplars in phonology. In J. A. Goldsmith, J. Riggle, & A. C. Yu (Eds.), The handbook of phonological theory (2nd ed.) (pp. 374-400). Oxford: Wiley-Blackwell.
  • Ernestus, M., & Warner, N. (2011). An introduction to reduced pronunciation variants [Editorial]. Journal of Phonetics, 39(SI), 253-260. doi:10.1016/S0095-4470(11)00055-6.

    Abstract

    Words are often pronounced very differently in formal speech than in everyday conversations. In conversational speech, they may contain weaker segments, fewer sounds, and even fewer syllables. The English word yesterday, for instance, may be pronounced as [j epsilon integral eI]. This article forms an introduction to the phenomenon of reduced pronunciation variants and to the eight research articles in this issue on the characteristics, production, and comprehension of these variants. We provide a description of the phenomenon, addressing its high frequency of occurrence in casual conversations in various languages, the gradient nature of many reduction processes, and the intelligibility of reduced variants to native listeners. We also describe the relevance of research on reduced variants for linguistic and psychological theories as well as for applications in speech technology and foreign language acquisition. Since reduced variants occur more often in spontaneous than in formal speech, they are hard to study in the laboratory under well controlled conditions. We discuss the advantages and disadvantages of possible solutions, including the research methods employed in the articles in this special issue, based on corpora and experiments. This article ends with a short overview of the articles in this issue.
  • Ernestus, M. (2011). Gradience and categoricality in phonological theory. In M. Van Oostendorp, C. J. Ewen, E. Hume, & K. Rice (Eds.), The Blackwell companion to phonology (pp. 2115-2136). Wiley-Blackwell.
  • Ernestus, M., & Warner, N. (Eds.). (2011). Speech reduction [Special Issue]. Journal of Phonetics, 39(SI).
  • Hanique, I., & Ernestus, M. (2011). Final /t/ reduction in Dutch past-participles: The role of word predictability and morphological decomposability. In Proceedings of the 12th Annual Conference of the International Speech Communication Association (Interspeech 2011), Florence, Italy (pp. 2849-2852).

    Abstract

    This corpus study demonstrates that the realization of wordfinal /t/ in Dutch past-participles in various speech styles is affected by a word’s predictability and paradigmatic relative frequency. In particular, /t/s are shorter and more often absent if the two preceding words are more predictable. In addition, /t/s, especially in irregular verbs, are more reduced, the lower the verb’s lemma frequency relative to the past-participle’s frequency. Both effects are more pronounced in more spontaneous speech. These findings are expected if speech planning plays an important role in speech reduction. Index Terms: pronunciation variation, acoustic reduction, corpus research, word predictability, morphological decomposability
  • Janse, E., & Ernestus, M. (2011). The roles of bottom-up and top-down information in the recognition of reduced speech: Evidence from listeners with normal and impaired hearing. Journal of Phonetics, 39(3), 330-343. doi:10.1016/j.wocn.2011.03.005.
  • Kuzla, C., & Ernestus, M. (2011). Prosodic conditioning of phonetic detail in German plosives. Journal of Phonetics, 39, 143-155. doi:10.1016/j.wocn.2011.01.001.

    Abstract

    This study investigates the prosodic conditioning of phonetic details which are candidate cues to phonological contrasts. German /b, d, g, p, t, k/ were examined in three prosodic positions. Lenis plosives /b, d, g/ were produced with less glottal vibration at larger prosodic boundaries, whereas their VOT showed no effect of prosody. VOT of fortis plosives /p, t, k/ decreased at larger boundaries, as did their burst intensity maximum. Vowels (when measured from consonantal release) following fortis plosives and lenis velars were shorter after larger boundaries. Closure duration, which did not contribute to the fortis/lenis contrast, was heavily affected by prosody. These results support neither of the hitherto proposed accounts of prosodic strengthening (Uniform Strengthening and Feature Enhancement). We propose a different account, stating that the phonological identity of speech sounds remains stable not only within, but also across prosodic positions (contrast-over-prosody hypothesis). Domain-initial strengthening hardly diminishes the contrast between prosodically weak fortis and strong lenis plosives.
  • Schuppler, B., Ernestus, M., Scharenborg, O., & Boves, L. (2011). Acoustic reduction in conversational Dutch: A quantitative analysis based on automatically generated segmental transcriptions [Letter to the editor]. Journal of Phonetics, 39(1), 96-109. doi:10.1016/j.wocn.2010.11.006.

    Abstract

    In spontaneous, conversational speech, words are often reduced compared to their citation forms, such that a word like yesterday may sound like [’jεsmall eshei]. The present chapter investigates such acoustic reduction. The study of reduction needs large corpora that are transcribed phonetically. The first part of this chapter describes an automatic transcription procedure used to obtain such a large phonetically transcribed corpus of Dutch spontaneous dialogues, which is subsequently used for the investigation of acoustic reduction. First, the orthographic transcriptions were adapted for automatic processing. Next, the phonetic transcription of the corpus was created by means of a forced alignment using a lexicon with multiple pronunciation variants per word. These variants were generated by applying phonological and reduction rules to the canonical phonetic transcriptions of the words. The second part of this chapter reports the results of a quantitative analysis of reduction in the corpus on the basis of the generated transcriptions and gives an inventory of segmental reductions in standard Dutch. Overall, we found that reduction is more pervasive in spontaneous Dutch than previously documented.
  • Ten Bosch, L., Hämäläinen, A., & Ernestus, M. (2011). Assessing acoustic reduction: Exploiting local structure in speech. In Proceedings of the 12th Annual Conference of the International Speech Communication Association (Interspeech 2011), Florence, Italy (pp. 2665-2668).

    Abstract

    This paper presents a method to quantify the spectral characteristics of reduction in speech. Hämäläinen et al. (2009) proposes a measure of spectral reduction which is able to predict a substantial amount of the variation in duration that linguistically motivated variables do not account for. In this paper, we continue studying acoustic reduction in speech by developing a new acoustic measure of reduction, based on local manifold structure in speech. We show that this measure yields significantly improved statistical models for predicting variation in duration.
  • Torreira, F., & Ernestus, M. (2011). Realization of voiceless stops and vowels in conversational French and Spanish. Laboratory Phonology, 2(2), 331-353. doi:10.1515/LABPHON.2011.012.

    Abstract

    The present study compares the realization of intervocalic voiceless stops and vowels surrounded by voiceless stops in conversational Spanish and French. Our data reveal significant differences in how these segments are realized in each language. Spanish voiceless stops tend to have shorter stop closures, display incomplete closures more often, and exhibit more voicing than French voiceless stops. As for vowels, more cases of complete devoicing and greater degrees of partial devoicing were found in French than in Spanish. Moreover, all French vowel types exhibit significantly lower F1 values than their Spanish counterparts. These findings indicate that the extent of reduction that a segment type can undergo in conversational speech can vary significantly across languages. Language differences in coarticulatory strategies and “base-of-articulation” are discussed as possible causes of our observations.
  • Torreira, F., & Ernestus, M. (2011). Vowel elision in casual French: The case of vowel /e/ in the word c’était. Journal of Phonetics, 39(1), 50 -58. doi:10.1016/j.wocn.2010.11.003.

    Abstract

    This study investigates the reduction of vowel /e/ in the French word c’était /setε/ ‘it was’. This reduction phenomenon appeared to be highly frequent, as more than half of the occurrences of this word in a corpus of casual French contained few or no acoustic traces of a vowel between [s] and [t]. All our durational analyses clearly supported a categorical absence of vowel /e/ in a subset of c’était tokens. This interpretation was also supported by our finding that the occurrence of complete elision and [e] duration in non-elision tokens were conditioned by different factors. However, spectral measures were consistent with the possibility that a highly reduced /e/ vowel is still present in elision tokens in spite of the durational evidence for categorical elision. We discuss how these findings can be reconciled, and conclude that acoustic analysis of uncontrolled materials can provide valuable information about the mechanisms underlying reduction phenomena in casual speech.
  • De Vaan, L., Ernestus, M., & Schreuder, R. (2011). The lifespan of lexical traces for novel morphologically complex words. The Mental Lexicon, 6, 374-392. doi:10.1075/ml.6.3.02dev.

    Abstract

    This study investigates the lifespans of lexical traces for novel morphologically complex words. In two visual lexical decision experiments, a neologism was either primed by itself or by its stem. The target occurred 40 trials after the prime (Experiments 1 & 2), after a 12 hour delay (Experiment 1), or after a one week delay (Experiment 2). Participants recognized neologisms more quickly if they had seen them before in the experiment. These results show that memory traces for novel morphologically complex words already come into existence after a very first exposure and that they last for at least a week. We did not find evidence for a role of sleep in the formation of memory traces. Interestingly, Base Frequency appeared to play a role in the processing of the neologisms also when they were presented a second time and had their own memory traces.
  • Van de Ven, M., Tucker, B. V., & Ernestus, M. (2011). Semantic context effects in the comprehension of reduced pronunciation variants. Memory & Cognition, 39, 1301-1316. doi:10.3758/s13421-011-0103-2.

    Abstract

    Listeners require context to understand the highly reduced words that occur in casual speech. The present study reports four auditory lexical decision experiments in which the role of semantic context in the comprehension of reduced versus unreduced speech was investigated. Experiments 1 and 2 showed semantic priming for combinations of unreduced, but not reduced, primes and low-frequency targets. In Experiment 3, we crossed the reduction of the prime with the reduction of the target. Results showed no semantic priming from reduced primes, regardless of the reduction of the targets. Finally, Experiment 4 showed that reduced and unreduced primes facilitate upcoming low-frequency related words equally if the interstimulus interval is extended. These results suggest that semantically related words need more time to be recognized after reduced primes, but once reduced primes have been fully (semantically) processed, these primes can facilitate the recognition of upcoming words as well as do unreduced primes.

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