F0 Difference Research Articles

School-age children benefit from voice gender cue differences for the perception of speech in competing speech.

Differences in speakers' voice characteristics, such as mean fundamental frequency (F0) and vocal-tract length (VTL), that primarily define speakers' so-called perceived voice gender facilitate the perception of speech in competing speech. Perceiving speech in competing speech is particularly challenging for children, which may relate to their lower sensitivity to differences in voice characteristics than adults. This study investigated the development of the benefit from F0 and VTL differences in school-age children (4-12 years) for separating two competing speakers while tasked with comprehending one of them and also the relationship between this benefit and their corresponding voice discrimination thresholds. Children benefited from differences in F0, VTL, or both cues at all ages tested. This benefit proportionally remained the same across age, although overall accuracy continued to differ from that of adults. Additionally, children's benefit from F0 and VTL differences and their overall accuracy were not related to their discrimination thresholds. Hence, although children's voice discrimination thresholds and speech in competing speech perception abilities develop throughout the school-age years, children already show a benefit from voice gender cue differences early on. Factors other than children's discrimination thresholds seem to relate more closely to their developing speech in competing speech perception abilities.

Intrinsic f0 and Sound Change: Evidence from Australian Languages

In this paper, a study is presented investigating two types of intrinsic f0 effects in sixteen Australian languages. Vowels are known to vary systematically in their mean f0 as a function of vowel height as well as voicing of the previous consonant, a property known as intrinsic f0. Vowel height has been known to have a positive correlation with f0, in which high vowels have a higher intrinsic f0 than low vowels on average. Differences in intrinsic f0 also vary systematically based on the voicing of a preceding stop, with voiceless stops correlating with higher intrinsic f0 and voiced stops with lower. Using automatic data processing methods on archival audio data, this study shows wide variation in the presence and robustness of intrinsic f0 effects in the Australian langauges investigated.

An Alternative Explanation for Difficulties with Speech in Background Talkers: Abnormal Fusion of Vowels Across Fundamental Frequency and Ears.

Normal-hearing (NH) listeners use frequency cues, such as fundamental frequency (voice pitch), to segregate sounds into discrete auditory streams. However, many hearing-impaired (HI) individuals have abnormally broad binaural pitch fusion which leads to fusion and averaging of the original monaural pitches into the same stream instead of segregating the two streams (Oh and Reiss, 2017) and may similarly lead to fusion and averaging of speech streams across ears. In this study, using dichotic speech stimuli, we examined the relationship between speech fusion and vowel identification. Dichotic vowel perception was measured in NH and HI listeners, with across-ear fundamental frequency differences varied. Synthetic vowels /i/, /u/, /a/, and /ae/ were generated with three fundamental frequencies (F0) of 106.9, 151.2, and 201.8Hz and presented dichotically through headphones. For HI listeners, stimuli were shaped according to NAL-NL2 prescriptive targets. Although the dichotic vowels presented were always different across ears, listeners were not informed that there were no single vowel trials and could identify one vowel or two different vowels on each trial. When there was no F0 difference between the ears, both NH and HI listeners were more likely to fuse the vowels and identify only one vowel. As ΔF0 increased, NH listeners increased the percentage of two-vowel responses, but HI listeners were more likely to continue to fuse vowels even with large ΔF0. Binaural tone fusion range was significantly correlated with vowel fusion rates in both NH and HI listeners. Confusion patterns with dichotic vowels differed from those seen with concurrent monaural vowels, suggesting different mechanisms behind the errors. Together, the findings suggest that broad fusion leads to spectral blending across ears, even for different ΔF0, and may hinder the stream segregation and understanding of speech in the presence of competing talkers.

No interaction between fundamental-frequency differences and spectral region when perceiving speech in a speech background

Differences in fundamental frequency (F0) or pitch between competing voices facilitate our ability to segregate a target voice from interferers, thereby enhancing speech intelligibility. Although lower-numbered harmonics elicit a stronger and more accurate pitch sensation than higher-numbered harmonics, it is unclear whether the stronger pitch leads to an increased benefit of pitch differences when segregating competing talkers. To answer this question, sentence recognition was tested in young normal-hearing listeners in the presence of a single competing talker. The stimuli were presented in a broadband condition or were highpass or lowpass filtered to manipulate the pitch accuracy of the voicing, while maintaining roughly equal speech intelligibility in the highpass and lowpass regions. Performance was measured with average F0 differences (ΔF0) between the target and single-talker masker of 0, 2, and 4 semitones. Pitch discrimination abilities were also measured to confirm that the lowpass-filtered stimuli elicited greater pitch accuracy than the highpass-filtered stimuli. No interaction was found between filter type and ΔF0 in the sentence recognition task, suggesting little or no effect of harmonic rank or pitch accuracy on the ability to use F0 to segregate natural voices, even when the average ΔF0 is relatively small. The results suggest that listeners are able to obtain some benefit of pitch differences between competing voices, even when pitch salience and accuracy is low.

Perception and production of [voice] contrasts in Dutch word-initial plosives

This study examines relative cue weights to the [voice] contrast in Dutch word-initial plosives. Perception and production data were collected from 25 native speakers, divided into two gender-balanced age groups (22-29; 61-71). Perception stimuli were artificially-manipulated continua /pɑd/-/bɑd/ ('trail', 'bath') and /tɑl/-/dɑl/ ('quantity', 'valley'), varying in amount of prevoicing and f0 of the following vowel. Results show that both prevoicing and f0 are used as cues to phonological voicing. Production results show an increasing rate of devoicing in younger participants, and significant f0 differences in all speakers. This suggests that cue weights are in the process of changing.

Effects of Hearing Loss on School-Aged Children's Ability to Benefit From F0 Differences Between Target and Masker Speech.

The objectives of the study were to (1) evaluate the impact of hearing loss on children's ability to benefit from F0 differences between target/masker speech in the context of aided speech-in-speech recognition and (2) to determine whether compromised F0 discrimination associated with hearing loss predicts F0 benefit in individual children. We hypothesized that children wearing appropriately fitted amplification would benefit from F0 differences, but they would not show the same magnitude of benefit as children with normal hearing. Reduced audibility and poor suprathreshold encoding that degrades frequency discrimination were expected to impair children's ability to segregate talkers based on F0. Listeners were 9 to 17 year olds with bilateral, symmetrical, sensorineural hearing loss ranging in degree from mild to severe. A four-alternative, forced-choice procedure was used to estimate thresholds for disyllabic word recognition in a 60-dB-SPL two-talker masker. The same male talker produced target and masker speech. Target words had either the same mean F0 as the masker or were digitally shifted higher than the masker by three, six, or nine semitones. The F0 benefit was defined as the difference in thresholds between the shifted-F0 conditions and the unshifted-F0 condition. Thresholds for discriminating F0 were also measured, using a three-alternative, three-interval forced choice procedure, to determine whether compromised sensitivity to F0 differences due to hearing loss would predict children's ability to benefit from F0. Testing was performed in the sound field, and all children wore their personal hearing aids at user settings. Children with hearing loss benefited from an F0 difference of nine semitones between target words and masker speech, with older children generally benefitting more than younger children. Some children benefitted from an F0 difference of six semitones, but this was not consistent across listeners. Thresholds for discriminating F0 improved with increasing age and predicted F0 benefit in the nine-semitone condition. An exploratory analysis indicated that F0 benefit was not significantly correlated with the four-frequency pure-tone average (0.5, 1, 2, and 4 kHz), aided audibility, or consistency of daily hearing aid use, although there was a trend for an association with the low-frequency pure-tone average (0.25 and 0.5 kHz). Comparisons of the present data to our previous study of children with normal hearing demonstrated that children with hearing loss benefitted less than children with normal hearing for the F0 differences tested. The results demonstrate that children with mild-to-severe hearing loss who wear hearing aids benefit from relatively large F0 differences between target and masker speech during aided speech-in-speech recognition. The size of the benefit increases with increasing age, consistent with previously reported age effects for children with normal hearing. However, hearing loss reduces children's ability to capitalize on F0 differences between talkers. Audibility alone does not appear to be responsible for this effect; aided audibility and degree of loss were not primary predictors of performance. The ability to benefit from F0 differences may be limited by immature central processing or aspects of peripheral encoding that are not characterized in standard clinical assessments.

Effect of Channel Interaction on Vocal Cue Perception in Cochlear Implant Users.

Speech intelligibility in multitalker settings is challenging for most cochlear implant (CI) users. One possibility for this limitation is the suboptimal representation of vocal cues in implant processing, such as the fundamental frequency (F0), and the vocal tract length (VTL). Previous studies suggested that while F0 perception depends on spectrotemporal cues, VTL perception relies largely on spectral cues. To investigate how spectral smearing in CIs affects vocal cue perception in speech-on-speech (SoS) settings, adjacent electrodes were simultaneously stimulated using current steering in 12 Advanced Bionics users to simulate channel interaction. In current steering, two adjacent electrodes are simultaneously stimulated forming a channel of parallel stimulation. Three such stimulation patterns were used: Sequential (one current steering channel), Paired (two channels), and Triplet stimulation (three channels). F0 and VTL just-noticeable differences (JNDs; Task 1), in addition to SoS intelligibility (Task 2) and comprehension (Task 3), were measured for each stimulation strategy. In Tasks 2 and 3, four maskers were used: the same female talker, a male voice obtained by manipulating both F0 and VTL (F0+VTL) of the original female speaker, a voice where only F0 was manipulated, and a voice where only VTL was manipulated. JNDs were measured relative to the original voice for the F0, VTL, and F0+VTL manipulations. When spectral smearing was increased from Sequential to Triplet, a significant deterioration in performance was observed for Tasks 1 and 2, with no differences between Sequential and Paired stimulation. Data from Task 3 were inconclusive. These results imply that CI users may tolerate certain amounts of channel interaction without significant reduction in performance on tasks relying on voice perception. This points to possibilities for using parallel stimulation in CIs for reducing power consumption.

Independent and Combined Effects of Fundamental Frequency and Vocal Tract Length Differences for School-Age Children's Sentence Recognition in a Two-Talker Masker.

Purpose The purpose of this study was to examine the independent and combined contributions of fundamental frequency (F0) and vocal tract length (VTL) differences on children's speech-in-speech recognition in the presence of a competing two-talker masker. Method Participants were 64 children (5-17 years old) and 25 adults (18-39 years old). Sentence recognition thresholds were measured in a two-talker masker. Target sentences had either the same mean F0 and VTL of the masker or were digitally altered so that the target and masker differed in F0 (Experiment 1), differed in VTL (Experiment 2), or differed in both F0 and VTL (Experiment 3). To determine the benefit, masking release was computed by subtracting thresholds in each shifted condition from the threshold in the unshifted condition. Results Results demonstrate that children's ability to benefit from either F0 or VTL differences (Experiments 1 and 2) depended on listener age, with younger children showing less improvement in speech reception thresholds compared to older children and adults. Age effects were also evident in the combined-cue conditions (Experiment 3), but children showed greater improvements compared to F0-only or VTL-only manipulations. Conclusions There was a prolonged pattern of development in children's ability to benefit from F0 or VTL differences between target and masker speech. Young children failed to capitalize on F0 and VTL differences to the same extent as older children and adults but did show a robust benefit when the cues were combined, supporting the hypothesis that younger children rely more heavily on redundant cues compared to older children and adults.

Speech Segregation in Active Middle Ear Stimulation: Masking Release With Changing Fundamental Frequency

Temporal fine structure information such as low-frequency sounds including the fundamental frequency (F0) is important to separate different talkers in noisy environments. Speech perception in noise is negatively affected by reduced temporal fine structure resolution in cochlear hearing loss. It has been shown that normal-hearing (NH) people as well as cochlear implant patients with preserved acoustic low-frequency hearing benefit from different F0 between concurrent talkers. Though patients with an active middle ear implant (AMEI) report better sound quality compared with hearing aids, they often struggle when listening in noise. The primary objective was to evaluate whether or not patients with a Vibrant Soundbridge AMEI were able to benefit from F0 differences in a concurrent talker situation and if the effect was comparable to NH individuals. A total of 13 AMEI listeners and 13 NH individuals were included. A modified variant of the Oldenburg sentence test was used to emulate a concurrent talker scenario. One sentence from the test corpus served as the masker and the remaining sentences as target speech. The F0 of the masker sentence was shifted upward by 4, 8, and 12 semitones. The target and masker sentences were presented simultaneously to the study subjects and the speech reception threshold was assessed by adaptively varying the masker level. To evaluate any impact of the occlusion effect on speech perception, AMEI listeners were tested in two configurations: with a plugged ear-canal contralateral to the implant side, indicated as AMEIcontra, or with both ears plugged, indicated as AMEIboth. In both study groups, speech perception improved when the F0 difference between target and masker increased. This was significant when the difference was at least 8 semitones; the F0-based release from masking was 3.0 dB in AMEIcontra (p = 0.009) and 2.9 dB in AMEIboth (p = 0.015), compared with 5.6 dB in NH listeners (p < 0.001). A difference of 12 semitones revealed a F0-based release from masking of 3.5 dB in the AMEIcontra (p = 0.002) and 3.4 dB in the AMEIboth (p = 0.003) condition, compared with 5.0 dB in NH individuals (p < 0.001). Though AMEI users deal with problems resulting from cochlear damage, hearing amplification with the implant enables a masking release based on F0 differences when F0 between a target and masker sentence was at least 8 semitones. Additional occlusion of the ear canal on the implant side did not affect speech performance. The current results complement the knowledge about the benefit of F0 within the acoustic low-frequency hearing.

Comparison of temporal fine structure sensitivity and concurrent vowel perception between children with and without reading disability.

Background: Children with reading deficits (RD) exhibit difficulty in perceiving speech in background noise due to poor auditory stream segregation. There is a dearth of literature on measures of temporal fine structure sensitivity (TFS) and concurrent vowel perception abilities to assess auditory stream segregation in children with reading deficits. Hence the present study compared temporal fine structure sensitivity (TFS) and concurrent vowel perception abilities between children with and without reading deficits. Method: The present research consisted of a total number of 30 participants, 15 children with reading deficits (RD) and fifteen typically developing (TD) children within the age range of 7-14 years and were designated as Group 1 and Group 2 respectively. Both groups were matched for age, grade, and classroom curricular instructions. The groups were evaluated for TFS and concurrent vowel perception abilities and the performance was compared using independent 't' test and repeated measure ANOVA respectively. Results: Results revealed that the children with RD performed significantly (p < 0.001) poorer than TD children on both TFS and concurrent vowel identification task. On concurrent vowel identification tasks, there was no significant interaction found between reading ability and F0 difference suggesting that the trend was similar in both the groups. Conclusion: The study concludes that the children with RD show poor temporal fine structure sensitivity and concurrent vowel identification scores compared to age and grade matched TD children owing to poor auditory stream segregation in children with RD.

An apparent-time study of an ongoing sound change in Seoul Korean: A prosodic account.

In present-day Seoul Korean, the primary phonetic feature for the lenis–aspirated stop distinction is shifting from VOT to F0. Some previous studies have considered this sound change to be a tonogenesis, whereby the low-level F0 perturbation has developed into tonal features (L for the lenis and H for the aspirated) in the segmental phonology. They, however, have examined the stop distinction only at a phrase- or utterance-initial position. We newly explore the sound change in relation to various prosodic structural factors (position and prominence). Apparent-time production data were recorded from four speaker groups: young female, young male, old female, old male. The way the speakers use VOT versus F0 indeed varies as a function of position and prominence. Crucially, in all groups, VOT is still used for the lenis–aspirated distinction phrase-medially due to the lenis stop voicing. This role of VOT, however, is found only in the non-prominent (unfocused) condition, in which the F0 difference is reduced to a low-level perturbation effect. In the prominent (focused) context in which tones come into play, the role of VOT diminishes, led by young female speakers. These can be interpreted as a prosodically-conditioned, complementary use of the features to maintain sufficient contrast. Importantly, however, the tonal difference under focus is not bidirectionally polarized, so that F0 is not lowered for the lenis stop. A lack of direct enhancement of the distinctive L tone weakens a possibility that F0 is transphonologized to the phonemic feature system of the language. As an alternative to the view that tonal features are newly introduced in the segmental phonology, we propose a prosodic account: the sound change is best characterized as a prosodically-conditioned change in the use of the segmental voicing feature (implemented by VOT) versus already available post-lexical tones in the intonational phonology of Korean.

Second-language learners of French do not acquire habitual pitch values

Järvinen et al. (2013) find that native Finnish speakers have higher pitch in English, suggesting that habitual pitch can be learned during second language acquisition. The mean F0 of French may be higher than that of English (Pépiot 2014), and this study investigates whether native speakers of American English who are L2 learners of French show different mean F0 in their second language compared to their first, and whether this is affected by L2 proficiency. The study compared the average F0 in sentences spoken by 6 female L2 French speakers (3 high proficiency, 3 low proficiency) to their English F0, and to the F0 of 6 female L1 French speakers. The L2 French speakers' F0 showed no significant difference from their L1 English, but L1 French F0 was significantly higher than both English and L2 French (p &amp;lt; 0.01 in both cases). There was also no significant difference in F0 between the high-proficiency and low-proficiency L2 French speakers. This indicates that English-speaking L2 learners do not acquire the higher habitual pitch values of French, even as proficiency increases. A comparison with Järvinen et al's findings suggests that adaptation to L2 pitch may not be automatic and may vary by language.

Modeling concurrent vowel identification for shorter durations

Behavioral studies on concurrent vowels with shorter duration (50 ms) show that overall identification scores across fundamental frequency (F0) differences are reduced when compared to longer duration (200 ms). In this current study, we investigated the effect of shorter durations on concurrent vowel scores using the temporal responses of an auditory-nerve model (Zilany et al., 2014) with a modified version of the Meddis and Hewitt (1992) F0-guided vowel segregation algorithm. The F0 representations of 50 ms vowel pairs were reduced but could not fully account for reduced identification, suggesting a limited ability to avail an F0-guided vowel segregation cue. Thus, by limiting only this cue in the segregation algorithm for 200 ms, the model was qualitatively successful in capturing lower scores across F0 differences for 50 ms. This differential ability to utilize an F0-guided segregation cue might contribute to a variable F0 benefit across normal-hearing listeners. The model also predicted an improvement in identification scores of the second vowel of the pair, when the duration was increased from 50 ms to 200 ms. These model predictions suggest that the inability to utilize an F0-guided segregation cue at shorter durations can account for reduced concurrent vowel identification scores across F0 differences.

Multilingualism and acoustic correlates of breathiness and tone in Kuy

Previous work on tonogenesis has focused primarily on intergenerational differences in cue weighting (Kang 2014, Coetzee et al. 2018) and less so on other sociolinguistic and language usage factors (though see Brunelle 2009). The current study explores the relationship of these variables with acoustic measures of voice quality (H1*-H2*, H1*-A1*, H1*-A2*, H1*-A3*, CPP, F1, f0) in a modal-breathy distinction in 63 speakers of Kuy, a minority language of Thailand. Kuy speakers are historically quadrilingual in Kuy, Thai, Lao, and Khmer, but recent centralization of Thailand has led to greater Thai usage. Because Thai is tonal and lacks a voice quality distinction, speakers who use Thai more are hypothesized to weigh f0 moreheavily and other breathiness measures less heavily. We find that f0 differences are significantly larger for speakers who use Thai more, while H1*-H2*, H1*-A1*, H1*-A2*, and H1*-A3* differences are slightly, but significantly, smaller. F1 shows no effect. Unexpectedly, CPP differences are also significantly larger for speakers who use Thai more. The results suggest that increasing Thai bilingualism plays a role in shifting voice quality cue weights and, in particular, in increasing f0 cue weights, providing one mechanism by which bilingualism in a tonal language may help catalyze tonogenesis.

Effect of Spectral Contrast Enhancement on Speech-on-Speech Intelligibility and Voice Cue Sensitivity in Cochlear Implant Users.

Speech intelligibility in the presence of a competing talker (speech-on-speech; SoS) presents more difficulties for cochlear implant (CI) users compared with normal-hearing listeners. A recent study implied that these difficulties may be related to CI users' low sensitivity to two fundamental voice cues, namely, the fundamental frequency (F0) and the vocal tract length (VTL) of the speaker. Because of the limited spectral resolution in the implant, important spectral cues carrying F0 and VTL information are expected to be distorted. This study aims to address two questions: (1) whether spectral contrast enhancement (SCE), previously shown to enhance CI users' speech intelligibility in the presence of steady state background noise, could also improve CI users' SoS intelligibility, and (2) whether such improvements in SoS from SCE processing are due to enhancements in CI users' sensitivity to F0 and VTL differences between the competing talkers. The effect of SCE on SoS intelligibility and comprehension was measured in two separate tasks in a sample of 14 CI users with Cochlear devices. In the first task, the CI users were asked to repeat the sentence spoken by the target speaker in the presence of a single competing talker. The competing talker was the same target speaker whose F0 and VTL were parametrically manipulated to obtain the different experimental conditions. SoS intelligibility, in terms of the percentage of correctly repeated words from the target sentence, was assessed using the standard advanced combination encoder (ACE) strategy and SCE for each voice condition. In the second task, SoS comprehension accuracy and response times were measured using the same experimental setup as in the first task, but with a different corpus. In the final task, CI users' sensitivity to F0 and VTL differences were measured for the ACE and SCE strategies. The benefit in F0 and VTL discrimination from SCE processing was evaluated with respect to the improvement in SoS perception from SCE. While SCE demonstrated the potential of improving SoS intelligibility in CI users, this effect appeared to stem from SCE improving the overall signal to noise ratio in SoS rather than improving the sensitivity to the underlying F0 and VTL differences. A second key finding of this study was that, contrary to what has been observed in a previous study for childlike voice manipulations, F0 and VTL manipulations of a reference female speaker (target speaker) toward male-like voices provided a small but significant release from masking for the CI users tested. The present findings, together with those previously reported in the literature, indicate that SCE could serve as a possible background-noise-reduction strategy in commercial CI speech processors that could enhance speech intelligibility especially in the presence of background talkers that have longer VTLs compared with the target speaker.

An Acoustic Study of Communication Apprehension during English Oral Presentations by Japanese University Students

This study investigated the influence of communication apprehension and anxiety in second-language (L2) learning on oral performance of Japanese university students in terms of F0 (fundamental frequency) analysis. The participants were English-major students (3 males and 6 females) who presented at an oral communication festival for university students. The F0 analysis consisted of a mean F0 and F0 range. The participants&amp;rsquo; utterances were digitized and analysed with Praat. Participants also completed two structured closed-ended questionnaires: a Personal Report of Communication Apprehension (PRCA) and a Foreign Language Classroom Anxiety Scale (FLCAS). One subscale of PRCA is Speech Anxiety (SA) that measures apprehension in public speaking. Acoustic analysis of F0 was conducted of the utterances provided by the students and their F0 data during rehearsal and the actual performance settings. The results revealed a significant difference in mean F0 between the rehearsal and actual performance. Mean F0 was significantly correlated with SA. These results suggest that students tend to show higher speech anxiety during an actual performance setting that is also reflected by a higher speaking F0.

Lexical ambiguity and acoustic distance in discrimination

This work presents a perceptual study on how acoustic details and knowledge of the lexicon influence discrimination decisions. English-speaking listeners were less likely to identify phonologically matching items as the same when they differed in vowel duration, but differences in mean F0 did not have an effect. Although both are components of English contrasts, the results only provide evidence for attention to vowel duration as a potentially contrastive cue. Lexical ambiguity was a predictor of response time. Pairs with matching duration were identified more quickly than pairs with distinct duration, but only among lexically ambiguous items, indicating that lexical ambiguity mediates attention to acoustic detail. Lexical ambiguity also interacted with neighborhood density: Among lexically unambiguous words, the proportion of 'same' responses decreased with neighborhood density, but there was no effect among lexically ambiguous words. This interaction suggests that evaluating phonological similarity depends more on lexical information when the items are lexically unambiguous.

Evaluating the effects of smoking on the voice and subjective voice problems using a meta-analysis approach

The objectives of this study were to identify the effects of smoking on the voice of smokers and present the baseline data for establishing the basis for preventing voice disorders. This study was evaluated using a meta-analysis from studies published between Jan 1, 2000, and Nov 15, 2018. As a result, the final meta-analysis was conducted using nine papers. The standard mean difference was analyzed after dividing the effects of smoking on voice into the pitch (F0), sound quality (jitter, shimmer, and noise to harmonic ratio; NHR), Maximum Phonation Time (MPT), and subjective voice problem. The results showed that there was a significant difference in F0 and MPT. On the other hand, the jitter, shimmer, NHR, and Voice Handicap Index (VHI) had different mean effect size but they were not significantly different. The analysis by sub-function of VHI results showed that the mean effect size was significantly different only in VHI-P (Physical). This study evaluated the effects of smoking on voice using meta-analysis. It was confirmed that smoking had significant and moderate effects on the F0 of voice, MPT, VHI, and physical functions. It is necessary for future meta-analysis studies to conduct randomized controlled experiments or longitudinal studies to confirm the effect sizes of variables.

Individual differences in human voice pitch are preserved from speech to screams, roars and pain cries.

Fundamental frequency (F0, perceived as voice pitch) predicts sex and age, hormonal status, mating success and a range of social traits, and thus functions as an important biosocial marker in modal speech. Yet, the role of F0 in human nonverbal vocalizations remains unclear, and given considerable variability in F0 across call types, it is not known whether F0 cues to vocalizer attributes are shared across speech and nonverbal vocalizations. Here, using a corpus of vocal sounds from 51 men and women, we examined whether individual differences in F0 are retained across neutral speech, valenced speech and nonverbal vocalizations (screams, roars and pain cries). Acoustic analyses revealed substantial variability in F0 across vocal types, with mean F0 increasing as much as 10-fold in screams compared to speech in the same individual. Despite these extreme pitch differences, sexual dimorphism was preserved within call types and, critically, inter-individual differences in F0 correlated across vocal types (r = 0.36–0.80) with stronger relationships between vocal types of the same valence (e.g. 38% of the variance in roar F0 was predicted by aggressive speech F0). Our results indicate that biologically and socially relevant indexical cues in the human voice are preserved in simulated valenced speech and vocalizations, including vocalizations characterized by extreme F0 modulation, suggesting that voice pitch may function as a reliable individual and biosocial marker across disparate communication contexts.

Acoustic parameters of courtship and human-directed friendly vocalisations in seven species of Neotropical deer in captivity

Context Polygynous deer rut vocalisations have been found to be highly conspicuous, typical of the species and important in sexual selection. Information about vocalisations is not available for Neotropical species (subfamily Odocoileinae). Aims The objective was to record courtship vocalisations from all Neotropical deer available, looking for differences among species useful for taxonomic identification, characterise the vocalisations according to acoustic parameters and to try to determine functions. Methods Four species of brocket deer (red, Mazama americana (n = 9); grey, M. gouazoubira (n = 7); Amazonian brown, M. nemorivaga (n = 3); Brazilian dwarf, M. nana (n = 1)), and one individual each of marsh (Blastocerus dichotomus), white-tailed (Odocoileus virginianus) and taruca (Hippocamellus antisensis) deer were recorded in captivity at two institutions, in conditions of courtship or human interaction. The acoustic analysis was performed with Praat. Data from the first three species of Mazama were analysed statistically with a multilevel model with two layers. Key results In the context of courting either females or humans, male deer produced low-intensity, short-duration (0.1–0.3 s) bleats with fundamental frequencies (F0) between 100 and 400 Hz; calls were similar among species. The duration of these calls for Amazonian brown brocket males was significantly longer than for males of the other two species. Females of two species had longer-duration calls than did males, in friendly interactions with humans. F0 differences among species for both friendly and courtship calls were almost significant for males of M. gouazoubira. Individual differences were highly significant for both duration and mean F0. Mean F0 for courtship calls of adult males was not correlated with body size in six of the seven species, in contrast to the theory of acoustic allometry. Conclusions The production of male courtship bleats is probably a basic feature of Odocoiline deer and is probably important in sexual selection and female choice. The differences from one species to another are not sufficient for taxonomic use but may be incipient isolating mechanisms between grey and Amazonian brown brocket deer. Implications Studies of deer vocalisations have shown their importance in sexual selection and their incredible variety in closely related species and subspecies, but they have dealt mainly with Old World deer. This study fills a gap in our knowledge, as the first on Neotropical deer, which constitute six genera and 17 species and are widely distributed in the Americas. These data are important for future studies on the function and phylogeny of deer vocalisations.