Optimization-based modeling of Lombard speech articulation: Supraglottal characteristics.

This paper shows that a highly simplified model of speech production based on the optimization of articulatory effort versus intelligibility can account for some observed articulatory consequences of signal-to-noise ratio. Simulations of static vowels in the presence of various background noise levels show that the model predicts articulatory and acoustic modifications of the type observed in Lombard speech. These features were obtained only when the constraint applied to articulatory effort decreases as the level of background noise increases. These results support the hypothesis that Lombard speech is listener oriented and speakers adapt their articulation in noisy environments.

Comparative Analysis of Majority Language Influence on North Sámi Prosody Using WaveNet-Based modeling.

The Finnmark North Sámi is a variety of North Sámi language, an indigenous, endangered minority language spoken in the northernmost parts of Norway and Finland. The speakers of this language are bilingual, and regularly speak the majority language (Finnish or Norwegian) as well as their own North Sámi variety. In this paper we investigate possible influences of these majority languages on prosodic characteristics of Finnmark North Sámi, and associate them with prosodic patterns prevalent in the majority languages. We present a novel methodology that: (a) automatically finds the portions of speech (words) where the prosodic differences based on majority languages are most robustly manifested; and (b) analyzes the nature of these differences in terms of intonational patterns. For the first step, we trained convolutional WaveNet speech synthesis models on North Sámi speech material, modified to contain purely prosodic information, and used conditioning embeddings to find words with the greatest differences between the varieties. The subsequent exploratory analysis suggests that the differences in intonational patterns between the two Finnmark North Sámi varieties are not manifested uniformly across word types (based on part-of-speech category). Instead, we argue that the differences reflect phrase-level prosodic characteristics of the majority languages.

Fluency-related Temporal Features and Syllable Prominence as Prosodic Proficiency Predictors for Learners of English with Different Language Backgrounds.

Prosodic features are important in achieving intelligibility, comprehensibility, and fluency in a second or foreign language (L2). However, research on the assessment of prosody as part of oral proficiency remains scarce. Moreover, the acoustic analysis of L2 prosody has often focused on fluency-related temporal measures, neglecting language-dependent stress features that can be quantified in terms of syllable prominence. Introducing the evaluation of prominence-related measures can be of use in developing both teaching and assessment of L2 speaking skills. In this study we compare temporal measures and syllable prominence estimates as predictors of prosodic proficiency in non-native speakers of English with respect to the speaker's native language (L1).The predictive power of temporal and prominence measures was evaluated for utterance-sized samples produced by language learners from four different L1 backgrounds: Czech, Slovak, Polish, and Hungarian. Firstly, the speech samples were assessed using the revised Common European Framework of Reference scale for prosodic features. The assessed speech samples were then analyzed to derive articulation rate and three fluency measures. Syllable-level prominence was estimated by a continuous wavelet transform analysis using combinations of F0, energy, and syllable duration.The results show that the temporal measures serve as reliable predictors of prosodic proficiency in the L2, with prominence measures providing a small but significant improvement to prosodic proficiency predictions. The predictive power of the individual measures varies both quantitatively and qualitatively depending on the L1 of the speaker. We conclude that the possible effects of the speaker's L1 on the production of L2 prosody in terms of temporal features as well as syllable prominence deserve more attention in applied research and developing teaching and assessment methods for spoken L2.

Dialectal variation of duration patterns in Finnmark North Sámi quantity.

Ternary length contrast is a rare phonological feature, investigated here both in terms of its realization and possible undergoing changes. In North Sámi, a phonetically under-documented and endangered Fenno-Ugric language spoken by indigenous people in Northern Europe, the ternary quantity contrast is assumed to be signalled by a progressive lengthening of a consonant and a compensatory shortening of the previous vowel. This study evaluates this assumption and compares the realization of the length contrasts in two dialects, the Western and Eastern Finnmark North Sámi. The results show that while the contrast between the short and the two longer quantities is robustly signaled regardless of the dialect, the durational differences between the two longer quantities are maintained only in the Eastern dialect. On the other hand, a vowel quantity contrast independent of the quantity of the following consonant is present in the Western but not in the Eastern dialect. Further, comparing the phonetic realization of the ternary quantity contrast for speakers of different ages presents evidence of a language change: the results indicate an ongoing neutralization of the ternary contrast in younger speakers, which points to a possible disappearance of this rare typological feature in Finnmark North Sámi.

The influence of fundamental frequency on perceived duration in spectrally comparable sounds.

The perceived duration of a sound is affected by its fundamental frequency and intensity: higher sounds are judged to be longer, as are sounds with greater intensity. Since increasing intensity lengthens the perceived duration of the auditory object, and increasing the fundamental frequency increases the sound's perceived loudness (up to ca. 3 kHz), frequency modulation of duration could be potentially explained by a confounding effect where the primary cause of the modulation would be variations in intensity. Here, a series of experiments are described that were designed to disentangle the contributions of fundamental frequency, intensity, and duration to perceived loudness and duration. In two forced-choice tasks, participants judged duration and intensity differences between two sounds varying simultaneously in intensity, fundamental frequency, fundamental frequency gliding range, and duration. The results suggest that fundamental frequency and intensity each have an impact on duration judgments, while frequency gliding range did not influence the present results. We also demonstrate that the modulation of perceived duration by sound fundamental frequency cannot be fully explained by the confounding relationship between frequency and intensity.

Musical Sophistication and the Effect of Complexity on Auditory Discrimination in Finnish Speakers.

Musical experiences and native language are both known to affect auditory processing. The present work aims to disentangle the influences of native language phonology and musicality on behavioral and subcortical sound feature processing in a population of musically diverse Finnish speakers as well as to investigate the specificity of enhancement from musical training. Finnish speakers are highly sensitive to duration cues since in Finnish, vowel and consonant duration determine word meaning. Using a correlational approach with a set of behavioral sound feature discrimination tasks, brainstem recordings, and a musical sophistication questionnaire, we find no evidence for an association between musical sophistication and more precise duration processing in Finnish speakers either in the auditory brainstem response or in behavioral tasks, but they do show an enhanced pitch discrimination compared to Finnish speakers with less musical experience and show greater duration modulation in a complex task. These results are consistent with a ceiling effect set for certain sound features which corresponds to the phonology of the native language, leaving an opportunity for music experience-based enhancement of sound features not explicitly encoded in the language (such as pitch, which is not explicitly encoded in Finnish). Finally, the pattern of duration modulation in more musically sophisticated Finnish speakers suggests integrated feature processing for greater efficiency in a real world musical situation. These results have implications for research into the specificity of plasticity in the auditory system as well as to the effects of interaction of specific language features with musical experiences.

Connections of Grasping and Horizontal Hand Movements with Articulation in Czech Speakers.

We have recently shown in Finnish speakers that articulation of certain vowels and consonants has a systematic influence on simultaneous grasp actions as well as on forward and backward hand movements. Here we studied whether these effects generalize to another language, namely Czech. We reasoned that if the results generalized to another language environment, it would suggest that the effects arise through other processes than language-dependent semantic associations. Rather, the effects would be likely to arise through language-independent interactions between processes that plan articulatory gestures and hand movements. Participants were presented with visual stimuli specifying articulations to be uttered (e.g., A or I), and they were required to produce a manual response concurrently with the articulation. In Experiment 1 they responded with a precision or a power grip, whereas in Experiment 2 they responded with a forward or a backward hand movement. The grip congruency effect was fully replicated: the consonant [k] and the vowel [α] were associated with power grip responses, while the consonant [t] and the vowel [i] were associated with precision grip responses. The forward/backward congruency effect was replicated with vowels [α], [o], which were associated with backward movement and with [i], which was associated with forward movement, but not with consonants [k] and [t]. These findings suggest that the congruency effects mostly reflect interaction between processes that plan articulatory gestures and hand movements with an exception that the forward/backward congruency effect might only work with vowel articulation.

Quantity language speakers show enhanced subcortical processing.

The complex auditory brainstem response (cABR) can reflect language-based plasticity in subcortical stages of auditory processing. It is sensitive to differences between language groups as well as stimulus properties, e.g. intensity or frequency. It is also sensitive to the synchronicity of the neural population stimulated by sound, which results in increased amplitude of wave V. Finnish is a full-fledged quantity language, in which word meaning is dependent upon duration of the vowels and consonants. Previous studies have shown that Finnish speakers have enhanced behavioural sound duration discrimination ability and larger cortical mismatch negativity (MMN) to duration change compared to German and French speakers. The next step is to find out whether these enhanced duration discrimination abilities of quantity language speakers originate at the brainstem level. Since German has a complementary quantity contrast which restricts the possible patterns of short and long vowels and consonants, the current experiment compared cABR between nonmusician Finnish and German native speakers using seven short complex stimuli. Finnish speakers had a larger cABR peak amplitude than German speakers, while the peak onset latency was only affected by stimulus intensity and spectral band. The results suggest that early cABR responses are better synchronised for Finns, which could underpin the enhanced duration sensitivity of quantity language speakers.

Hyperarticulation in Lombard speech: Global coordination of the jaw, lips and the tongue.

Over the last century, researchers have collected a considerable amount of data reflecting the properties of Lombard speech, i.e., speech in a noisy environment. The documented phenomena predominately report effects on the speech signal produced in ambient noise. In comparison, relatively little is known about the underlying articulatory patterns of Lombard speech, in particular for lingual articulation. Here the authors present an analysis of articulatory recordings of speech material in babble noise of different intensity levels and in hypoarticulated speech and report quantitative differences in relative expansion of movement of different articulatory subsystems (the jaw, the lips and the tongue) as well as in relative expansion of utterance duration. The trajectory modifications for one articulator can be relatively reliably predicted by those for another one, but subsystems differ in a degree of continuity in trajectory expansion elicited across different noise levels. Regression analysis of articulatory modifications against durational expansion shows further qualitative differences between the subsystems, namely, the jaw and the tongue. The findings are discussed in terms of possible influences of a combination of prosodic, segmental, and physiological factors. In addition, the Lombard effect is put forward as a viable methodology for eliciting global articulatory variation in a controlled manner.

Stability and Variability in Slovak Prosodic Boundaries.

BACKGROUND/AIM: Encoding intended meanings in the type and strength of prosodic boundaries and strategies for communicating these meanings in ambient noise use similar prosodic cues. We analyze how increasing the level of ambient noise affects the realization of Slovak prosodic boundaries. METHODS: Five native speakers of Slovak read sentences, manipulating the boundary type (weak, rise, fall) and the location of pre-boundary pitch accent. Ambient noise of several levels was administered via headphones. Acoustic and articulatory data (electromagnetometry) were collected. RESULTS: Under normal condition, boundary strength is signaled with longer pre-boundary rhymes, more frequent pauses, greater crossboundary f0 resets and jaw displacement. The strength of falls is realized in crossboundary features (pauses, f0 reset), and rises in pre-boundary features (rhyme duration, f0 range). Pitch-accented rhymes are strengthened in all features, but f0 range. In noise, the increase in boundary strength is weak, and falls strengthen more than rises. F0 targets for falls and rises are adjusted in addition to noiseinduced global f0 scaling and lengthening. CONCLUSION: Hyper-articulation of prosodic boundaries in ambient noise is not robust and uniform; rather, durational, f0 and jaw displacement features co-create complex prosodic patterns in a complementary and synergetic manner based on affordances in normal speech.

Embodied task dynamics.

Movement science faces the challenge of reconciling parallel sequences of discrete behavioral goals with observed fluid, context-sensitive motion. This challenge arises with a vengeance in the speech domain, in which gestural primitives play the role of discrete goals. The task dynamic framework has proved effective in modeling the manner in which the gestural primitives of articulatory phonology can result in smooth, biologically plausible, movement of model articulators. We present a variant of the task dynamic model with 1 significant innovation: Tasks are not abstract and context free but are embodied and tied to specific effectors. An advantage of this approach is that it allows the definition of a parametric cost function that can be optimized. Optimization generates gestural scores in which the relative timing of gestures is fully specified. We demonstrate that movements generated in an optimal manner are phonetically plausible. Highly nuanced movement trajectories are emergent based on relatively simple optimality criteria. This addresses a long-standing need within this theoretical framework and provides a rich modeling foundation for subsequent work.