Effect of being seen on the production of visible speech cues. A pilot study on Lombard speech

International audienceSpeech produced in noise (or Lombard speech) is characterized by increased vocal effort, but also by amplified lip gestures. The current study examines whether this enhancement of visible speech cues may be sought by the speaker, even unconsciously, in order to improve his visual intelligibility. One subject played an interactive game in a quiet situation and then in 85dB of cocktail-party noise, for three conditions of interaction: without interaction, in face-to-face interaction, and in a situation of audio interaction only. The audio signal was recorded simultaneously with articulatory movements, using 3D electromagnetic articulography. The results showed that acoustic modifications of speech in noise were greater when the interlocutor could not see the speaker. Furthermore, tongue movements that are hardly visible were not particularly amplified in noise. Lip movements that are very visible were not more enhanced in noise when the interlocutors could see each other. Actually, they were more enhanced in the situation of audio interaction only. These results support the idea that this speaker did not make use of the visual channel to improve his intelligibility, and that his hyper articulation was just an indirect correlate of increased vocal effort

Pitch in native and non-native Lombard speech

Lombard speech, speech produced in noise, is typically produced with a higher fundamental frequency (F0, pitch) compared to speech in quiet. This paper examined the potential differences in native and non-native Lombard speech by analyzing median pitch in sentences with early- or late-focus produced in quiet and noise. We found an increase in pitch in late-focus sentences in noise for Dutch speakers in both English and Dutch, and for American-English speakers in English. These results show that non-native speakers produce Lombard speech, despite their higher cognitive load. For the early-focus sentences, we found a difference between the Dutch and the American-English speakers. Whereas the Dutch showed an increased F0 in noise in English and Dutch, the American-English speakers did not in English. Together, these results suggest that some acoustic characteristics of Lombard speech, such as pitch, may be language-specific, potentially resulting in the native language influencing the non-native Lombard speech

Say again? Individual acoustic strategies for producing a clearly-spoken minimal pair wordlist

Paper number: 0769James Scobbie - ORCID: 0000-0003-4509-6782 https://orcid.org/0000-0003-4509-6782People make their speech clearer in difficult conversational contexts using global mechanisms (e.g. “Lombard Speech”) and by targeted enhancements of linguistic constituents (“hyperspeech”). We describe production changes observed in four speakers of Scottish English who produced three repetitions of twelve CVC words: V was one of six monophthongs and C_C was either /p_p/ or /m_m/. Thus each word differed (near-) minimally from six others. In a “neutral” condition each participant read aloud from a randomised wordlist. A “clear” condition was an interactive task in which an interlocutor had to repeat back every word correctly, despite their hearing being impaired by headphone-delivered noise. If the speaker was mis-perceived by the interlocutor, the speaker tried again, until the word was correctly repeated. We describe the surprisingly speaker-specific acoustic hyperspeech effects (in vowel F1, vowel space area, and acoustic segment durations) in the clear speech. A companion paper describes the associated articulatory changes.https://www.internationalphoneticassociation.org/content/icphspubpu

Say again? Individual articulatory strategies for producing a clearly-spoken minimal pair wordlist

Paper number: 0975James Scobbie - ORCID: 0000-0003-4509-6782 https://orcid.org/0000-0003-4509-6782We describe articulatory differences (lingual and labial) between two versions (neutral and clear) of a CVC wordlist of 12 targets (V = /ieaɔoʉ/; C_C = /p_p/ or /m_m/). A companion paper describes the background; the participants, materials and tasks; the impressionistic and acoustic results. Labial measures reflect vowel opening (and edge-spreading) and consonant compression using fleshpoint markers captured by head-mounted video. Consonant closure and total word duration are based on visual judgement of complete closure. Ultrasound data provides the absolute area between neutral and clear mid-sagittal tongue-surface splines at the maximum of each vowel target, and a qualitative description of tongue shape and location. Strong and systematic interspeaker variation was evident in how articulation, acoustics and functional clarity were enhanced. Some large phonologically motivated segmental hyperspeech enhancements were observed, but they were not related straightforwardly to the phonological oppositions in the material nor consistently used by all speakers. Differences in utterance initiation are also discussed.https://www.internationalphoneticassociation.org/content/icphspubpu

Per una caratterizzazione acustica del clear speech

La ricerca prende in esame alcuni aspetti acustici relativi al passaggio dal parlato \u2018normale\u2019 al parlato cosiddetto clear e affronta preliminarmente varie questioni di carattere terminologico e metodologico concernenti le indagini che si prefiggono di meglio comprendere questa modalit\ue0 d\u2019eloquio. I dati analizzati provengono da due parlanti di sesso maschile, uno italiano (Pisa), uno di lingua m\uf2or\ue9 (Ougadougou, Burkina Faso). Per il locutore pisano sono stati osservati i valori relativi alla velocit\ue0 d\u2019eloquio e alla durata, in maniera da poter verificare se il parlato clear sia complessivamente pi\uf9 lento. Per entrambi i parlanti sono stati misurati i valori formantici delle vocali toniche e l\u2019estensione dello spazio vocalico, in modo tale da appurare se esiste un legame tra l\u2019estensione dell\u2019inventario vocalico e la maggiore o minore tendenza verso il parlato clear

The Lombard intelligibility benefit of native and non-native speech for native and non-native listeners

Speech produced in noise (Lombard speech) is more intelligible than speech produced in quiet (plain speech). Previous research on the Lombard intelligibility benefit focused almost entirely on how native speakers produce and perceive Lombard speech. In this study, we investigate the size of the Lombard intelligibility benefit of both native (American-English) and non-native (native Dutch) English for native and non-native listeners (Dutch and Spanish). We used a glimpsing metric to measure the energetic masking potential of speech, which predicted that both native and non-native Lombard speech could withstand greater amounts of masking to a similar extent, compared to plain speech. In an intelligibility experiment, native English, Spanish, and Dutch listeners listened to the same words, mixed with noise. While the non-native listeners appeared to benefit more from Lombard speech than the native listeners did, each listener group experienced a similar benefit for native and non-native Lombard speech. Energetic masking, as captured by the glimpsing metric, only accounted for part of the Lombard benefit, indicating that the Lombard intelligibility benefit does not only result from a shift in spectral distribution. Despite subtle native language influences on non-native Lombard speech, both native and non-native speech provides a Lombard benefit

Acoustic features of infant-directed speech to infants with hearing loss

Published Online: 03 December 2020This study investigated the effects of hearing loss and hearing experience on the acoustic features of infant-directed speech (IDS) to infants with hearing loss (HL) compared to controls with normal hearing (NH) matched by either chronological or hearing age (experiment 1) and across development in infants with hearing loss as well as the relation between IDS features and infants' developing lexical abilities (experiment 2). Both experiments included detailed acoustic analyses of mothers' productions of the three corner vowels /a, i, u/ and utterance-level pitch in IDS and in adult-directed speech. Experiment 1 demonstrated that IDS to infants with HL was acoustically more variable than IDS to hearing-age matched infants with NH. Experiment 2 yielded no changes in IDS features over development; however, the results did show a positive relationship between formant distances in mothers' speech and infants' concurrent receptive vocabulary size, as well as between vowel hyperarticulation and infants' expressive vocabulary. These findings suggest that despite infants' HL and thus diminished access to speech input, infants with HL are exposed to IDS with generally similar acoustic qualities as are infants with NH. However, some differences persist, indicating that infants with HL might receive less intelligible speech.This research was supported by HEARing Cooperative Research Centre Grant No. 82631, “The Seeds of Language Development,” to D.B. The second author's work is supported by the Basque Government through the BERC 2018-2021 program and by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship PID2019-105528GA-I00. We would like to thank all the parents and infants for participating in the study; “The Shepherd Centre” in Sydney and Wollongong; “Hear and Say” in Brisbane for their help in recruitment of participants with HL; and Benjawan Kasisopa, Maria Christou-Ergos, Hana Zjakic, and Scott O'Loughlin for their assistance with data collection

EVALUATION OF THE SIGNAL-TO-NOISE RATIO REQUIRED TO ACHIEVE THE SAME PERFORMANCE IN ENGLISH AND MANDARIN CHINESE

Difficulty communicating in noise is a common complaint for people with hearing loss. When communicating in noise, speakers increase the intensity level of their voice and alter the stress patterns of their speech not only to monitor their own voice but also to be heard by others. Speech that increases in intensity for the purpose of self-monitoring and being understood in noise is called Lombard speech. Few studies have assessed communication performance with Lombard speech in noise which closely reflects the real-life communication situation. In addition, the characteristics of Lombard speech may be different(among) languages with different characteristics and identifying features so the few results available for English listeners may not apply to listeners of other languages. This study evaluated the performance of English speaking and Mandarin Chinese speaking individuals listening to English and Mandarin Chinese speech in corresponding babble noise. Speech materials were the IEEE sentences in English and translated into Mandarin Chinese while controlling for phonological, grammatical, and contextual predictability. The sentences and 4-talker babble were recorded in a conversational manner and at a Lombard speech level produced while listening to 80 dB SPL of noise. The performance of 18 native English speakers and 18 native Mandarin Chinese speakers was evaluated. The SNR-50, the signal-to-noise level required to produce 50% performance, was the same for conversational and Lombard English indicating that there is not a particular benefit in producing Lombard speech to be understood. The reason to produce Lombard speech in English is to improve the signal-to-noise ratio in order to facilitate improved communication. The results for the Mandarin Chinese listeners revealed a benefit when producing Lombard speech with the SNR-50 for Mandarin Chinese significantly different between conversational and Lombard speech. In noisy situations where increasing vocal intensity is expected, , Mandarin Chinese listeners appear to benefit from features preserved or enhanced through Lombard speech that English listeners do not access

Prototype modeling of vowel perception and production in a quantity language

Vowel prototypes refer to the psychological memory representations of the best exemplars of a vowel category. This thesis examines the role of prototypes in the perception and production of Finnish short and long vowels. A comparison with German as a linguistically different language with a similar vowel system is also made. The thesis reports on a series of four experiments in which prototypes are examined by means of behavioral psychoacoustic measurements and compared with vowel productions in quiet and in noise. In the perception experiments, Finnish and German listeners were asked to identify and evaluate the goodness of synthesized vowels representing either the entire vowel space or selected subareas of the space. In the production experiments, only Finnish speakers were recruited, but earlier reported production data were used for the comparison of Finnish and German. The new concept of the weighted prototype (Pω) is introduced in Study I, and its usability in contrast to absolute prototypes (Pa) and category centroids (Pc) is examined in Study IV. Generally, the results support the finding that vowel categories are not homogenous in quality, but have an internal structure, and that there are significant quality differences between category members in terms of goodness ratings. The results of Studies I, II and III support the identity group interpretation of the Finnish quantity opposition by showing that the differences in the perceived quality and in the produced short and long vowels are not demonstrably dependent on the physical duration of the stimuli, although the production experiments in Studies I and III indicated that the short peripheral vowels, especially /u/ in Study III, are more centralized in the vowel space than the long vowels. On the basis of the results of Study II, the spectral and durational local effective vowel indicators of the initial auditory theory of vowel perception appear to be independent of each other, thus suggesting that the auditory vowel space (AVS) is orthogonal in terms of the measures used in the experiment. Furthermore, the reaction time results of Study II indicate that stimulus typicality in terms of vowel quantity affects the categorization process of quality but not its end result. The noise masking of production in Study III indicated that both of the noise types applied in the experiment, pink noise and babble noise, resulted in a prolongation of all vowel durations as reported earlier on the Lombard effect. However, the noise masking did not affect the Euclidean distances between the short and long vowels, but caused a minor systematic drift on F1–F2 space in both vowel types. The minor differences suggest that prototypes act as articulatory targets in a fire-and-forget manner without the auditory feedback affecting the immediate articulation. The results concerning the different prototype measures indicated that the Pa and Pω differ significantly from the Pc, with the Pa being most peripheral. This gives some support to the adaptive dispersion effect in perception. The individual variations of the measures were normally distributed, with some exceptions for Pa in Finnish, and were, in terms of the coefficient of variation (CV), of the order of difference limen (DL) of frequency. These results suggest that, for normally distributed prototypes, and especially for Pω, which showed the least variation, two thirds of the subjects detected the best category representatives from a subset of stimuli that lie within the limits of DL of frequency from each other in the F1–F2 space. This finding can be regarded as a strong evidence for prototype theories, in other words, the best category representatives play a role by acting as templates in vowel perception. The listeners were able to recognize quality differences between and within vowel categories, but the majority of them ranked the best category exemplars from a subset of stimuli that were hardly distinguishable from each other. There were some minor differences in the vowel systems of Finnish and German as indicated by the different prototype measures: the absolute prototypes showed the largest differences between the languages in /e/, / ø/ and /u/. This is in line with the earlier investigations on produced vowels in Finnish and German. Generally, the vowel systems of these two linguistically unrelated languages were strikingly similar, especially in the light of the Pω measure. As presented in this thesis, the prototype approach provides a feasible tool for research and the results lend support to the idea that speech comprehension on the auditory, phonetic, and even on phonological processing levels is based on the memory representations of typical speech sounds of one’s native tongue, formed during the early language acquisition phase, and these representations may be similar for the speakers and listeners of two different languages with comparable vowel systems