Vocal Sequences Research Articles

Focal expression of mutant huntingtin in the songbird basal ganglia disrupts cortico-basal ganglia networks and vocal sequences

The basal ganglia (BG) promote complex sequential movements by helping to select elementary motor gestures appropriate to a given behavioral context. Indeed, Huntington's disease (HD), which causes striatal atrophy in the BG, is characterized by hyperkinesia and chorea. How striatal cell loss alters activity in the BG and downstream motor cortical regions to cause these disorganized movements remains unknown. Here, we show that expressing the genetic mutation that causes HD in a song-related region of the songbird BG destabilizes syllable sequences and increases overall vocal activity, but leave the structure of individual syllables intact. These behavioral changes are paralleled by the selective loss of striatal neurons and reduction of inhibitory synapses on pallidal neurons that serve as the BG output. Chronic recordings in singing birds revealed disrupted temporal patterns of activity in pallidal neurons and downstream cortical neurons. Moreover, reversible inactivation of the cortical neurons rescued the disorganized vocal sequences in transfected birds. These findings shed light on a key role of temporal patterns of cortico-BG activity in the regulation of complex motor sequences and show how a genetic mutation alters cortico-BG networks to cause disorganized movements.

Vocal complexity influences female responses to gelada male calls.

Extensive research indicates that inter-sexual selection drives the evolution of complex vocal communication in birds, but parallel lines of evidence are almost entirely absent in mammals. This dearth of evidence, particularly among primates, limits our understanding of the link between sociality and vocal complexity. Here, we use a playback experiment to quantify how wild female geladas (Theropithecus gelada) respond to three call types that are ‘derived’ (i.e., unique to geladas) and made by males during various affiliative contexts. These derived calls appeared to be highly salient and preferable to females: they looked longer towards and spent more time in proximity to playbacks of male vocal sequences containing one of the derived calls than to sequences containing only common and less elaborate ‘grunt’ calls. Our results provide the first experimental evidence for vocal elaboration as a male-specific strategy to maintain social bonds with females in non-human primates.

Harsh vocal elements affect counter-singing dynamics in male rock hyrax

Morton’s motivation-structural (MS) rules suggest that the acoustic structure of a signal can reflect the caller’s motivation and internal state. In many species, low-frequency and noisy (harsh) sounds have been found to comply with MS rules, accompanying agonistic interactions and functioning as a badge of aggression and dominance. Male rock hyraxes (Procavia capensis) often produce long and complex advertisement calls (songs) both spontaneously and in counter-singing sessions with other males. Hyrax songs include a vocal element, which is a harsh sound produced only by mature, dominant males. We predicted that the number of snort elements in the song would affect the dynamics of male hyrax counter-singing. We performed 3 series of playback experiments of natural and artificially manipulated songs on a wild hyrax population. We found that the probability of initiating counter-singing by nearby males increased together with the number of snorts in the stimulus song. Furthermore, the receivers replied to the synthetic snort-only vocal sequences at an equal rate as to their origin song as long as the snort elements maintained their original position within the signal. Our findings suggest that the snort component is one of the main information transfer channels in male hyrax singing and can elicit conspecific singing even when isolated from other vocal elements. In addition, the position of snort elements (their temporal pattern and rhythm) bears a possible significance in keeping the overall signal meaningful. Finally, our findings support previous claims that harsh sounds constitute one of the key components in vocal communication.

Forensic speaker comparison of Spanish twins and non-twin siblings: a phonetic-acoustic analysis of formant trajectories in vocalic sequences, glottal source parameters and cepstral characteristics

The objective of this thesis is to investigate the phonetic-acoustic similarities and differences in three main speaker groups: monozygotic (MZ) twins, dizygotic (DZ) twins and non-twin siblings. From a forensic-phonetic perspective, the study of this type of speakers is highly relevant, as they represent extreme examples of physical similarity. Distinguishing their voices poses a well-recognized challenge in the forensic realm [see Chapter 2]. Yet, there is an interest in this investigation per se, as the study of genetically identical speakers (MZ twins) and their comparison with non-genetically-identical siblings (DZ twins and non-twin siblings), on the one hand, and with a reference population of unrelated speakers, on the other hand, allows gaining insight into the contribution of nurture and nature in the speech patterns of speakers in general. In other words: to what extent is our voice determined by our DNA and to what extent is it due to educational influences? Besides, this study could be considered the first investigation into the phonetic and acoustic characteristics of Spanish-speaking twins and siblings. According to our research objective, a three-folded approach has been undertaken, as will be described below. For the 54 male speakers recorded ad hoc for this study, three different analyses have been carried out. On the one hand, we have labeled and analyzed the F1-F3 formant trajectories of 19 Spanish vocalic sequences. Secondly, several naturally sustained [e?] tokens have been extracted from the speakers? spontaneous vowel fillers and their glottal source characteristics have been analyzed. These two approaches have been complemented with an automatic speaker recognition analysis carried out with the software Batvox.

Two distinct representations of social vocalizations in the basolateral amygdala.

Acoustic communication signals carry information related to the types of social interactions by means of their "acoustic context," the sequencing and temporal emission pattern of vocalizations. Here we describe responses to natural vocal sequences in adult big brown bats (Eptesicus fuscus). We first assessed how vocal sequences modify the internal affective state of a listener (via heart rate). The heart rate of listening bats was differentially modulated by vocal sequences, showing significantly greater elevation in response to moderately aggressive sequences than appeasement or neutral sequences. Next, we characterized single-neuron responses in the basolateral amygdala (BLA) of awake, restrained bats to isolated syllables and vocal sequences. Two populations of neurons distinguished by background firing rates also differed in acoustic stimulus selectivity. Low-background neurons (<1 spike/s) were highly selective, responding on average to one tested stimulus. These may participate in a sparse code of vocal stimuli, in which each neuron responds to one or a few stimuli and the population responds to the range of vocalizations across behavioral contexts. Neurons with higher background rates (≥1 spike/s) responded broadly to tested stimuli and better represented the timing of syllables within sequences. We found that spike timing information improved the ability of these neurons to discriminate among vocal sequences and among the behavioral contexts associated with sequences compared with a rate code alone. These findings demonstrate that the BLA contains multiple robust representations of vocal stimuli that can provide the basis for emotional/physiological responses to these stimuli.

Sound production in the Ponto-Caspian gobyNeogobius fluviatilisand acoustic affinities within theGobiuslineage: implications for phylogeny

The aim of this study was to describe the vocal repertoire of the Ponto-Caspian goby Neogobius fluviatilis and to compare the acoustic properties of this species with those of other soniferous Mediterranean gobies belonging to the Gobius lineage. Vocalizations and associated behaviours were recorded under controlled aquarium conditions in female and male N. fluviatilis. Sound emission was elicited by means of ‘intruder tests’, using an individual of the same or opposite sex as an intruder, and recording sounds using a hydrophone placed 20 cm from the shelter used as a nest for the resident fish. Five acoustic properties, including spectral and temporal properties, were measured from 13 individuals. The vocal repertoire of the species consisted of sequences of short vocalizations during both agonistic and reproductive intraspecific interactions. The wave form of each sound resolved in a pure sine wave composed of rapidly repeated pulses. Sounds lasted about 200 ms, showing an average fundamental frequency of about 80 Hz. Sound properties did not differ between reproductive and the aggressive contexts, and the general structure of sounds was highly stereotyped. The individual means of three acoustic independent traits characterizing the sounds of seven species of the Gobius lineage, including N. fluviatilis, were then entered in a discriminant function analysis to assess how well species could be differentiated on the basis of acoustics, and their degree of affinities. The results suggested that the pulse repetition rate of the sounds, i.e. the relative tonal/pulsatile nature of the sounds, was the most important property in differentiating the species, and that this trait may contain a high level of phylogenetic signal, as the species producing tonal sounds clustered together, in line with the results of recent molecular phylogenic studies. The results were discussed in light of the geological and phylogeographical events believed to have driven the diversification of European gobies.

Vocal folds morphological pathologies detection using Gabor filtering and Principal Component Analysis.

Given the importance of the voice in our daily lives, any study focused on its pathologies and the way of caring and promoting the health of them is of common interest. This paper describes a method to automatically aid indetecting vocal folds benign pathologies based on glottal space segmentation vocal fold video sequences captured by a laryngoscope. The proposed algorithm is based on automatic segmentation supported by Gabor filters, and features classification with Principal Component Analysis (PCA) to achieve the expected results. The authors wish to emphasize that the proposed algorithm is independent from the images' resolution and zoom, but their quality depends on specialist experience with the instrumentation. Segmentation block provides good results for 95% of images and classification block distinguishes successfully between pathological and healthy images in 92.1% of cases. The proposed system's findings have been compared with the diagnosis made by doctors and it obtains the same results in all the 45 sequences. One of the proposed study's key elements has been which objective measurements are of significance for the specialist. In this case, it is those that enable the specialist to calculate the size of the pathology (previously classified automatically) that he/she is observing, thus enabling them to provide the patient with more information or to prescribe treatment and even measure its development.

Quantifying similarity in animal vocal sequences: which metric performs best?

SummaryMany animals communicate using sequences of discrete acoustic elements which can be complex, vary in their degree of stereotypy, and are potentially open‐ended. Variation in sequences can provide important ecological, behavioural or evolutionary information about the structure and connectivity of populations, mechanisms for vocal cultural evolution and the underlying drivers responsible for these processes. Various mathematical techniques have been used to form a realistic approximation of sequence similarity for such tasks.Here, we use both simulated and empirical data sets from animal vocal sequences (rock hyrax,Procavia capensis; humpback whale,Megaptera novaeangliae; bottlenose dolphin,Tursiops truncatus; andCarolina chickadee,Poecile carolinensis) to test which of eight sequence analysis metrics are more likely to reconstruct the information encoded in the sequences, and to test the fidelity of estimation of model parameters, when the sequences are assumed to conform to particular statistical models.Results from the simulated data indicated that multiple metrics were equally successful in reconstructing the information encoded in the sequences of simulated individuals (Markov chains,n‐gram models, repeat distribution and edit distance) and data generated by different stochastic processes (entropy rate andn‐grams). However, the string edit (Levenshtein) distance performed consistently and significantly better than all other tested metrics (including entropy,Markov chains,n‐grams, mutual information) for all empirical data sets, despite being less commonly used in the field of animal acoustic communication.TheLevenshtein distance metric provides a robust analytical approach that should be considered in the comparison of animal acoustic sequences in preference to other commonly employed techniques (such asMarkov chains, hiddenMarkov models orShannon entropy). The recent discovery that non‐Markovian vocal sequences may be more common in animal communication than previously thought provides a rich area for future research that requires non‐Markovian‐based analysis techniques to investigate animal grammars and potentially the origin of human language.

Impact of visual contact on vocal interaction dynamics of pair-bonded birds

Animal social interactions usually revolve around several sensory modalities. For birds, these are pri- marily visual and acoustic. However, some habitat specificities or long distances may temporarily hinder or limit visual information transmission making acoustic transmission a central channel of communi- cation even during complex social behaviours. Here we investigated the impact of visual limitation on the vocal dynamics between zebra finch, Taeniopygia guttata, partners. Pairs were acoustically recorded during a separation and reunion protocol with gradually decreasing distance without visual contact. Without visual contact, pairs displayed more correlated vocal exchanges than with visual contact. We also analysed the turn-taking sequences of individuals' vocalizations during an exchange with or without visual contact. In the absence of visual contact, the identity of a vocalizing individual was well predicted by the knowledge of the identity of the previous vocalizer. This property is characteristic of a stochastic process called a Markov chain and we found that turn-taking sequences of birds deprived of visual contact were Markovian. Thus, both the temporal correlation between the calls of the two partners and Markov properties of acoustic interactions indicate that, in the absence of visual cues, the decision to call is taken on a very short-term basis and solely on acoustic information (both temporal and identity of caller). Strikingly, when individuals were in visual contact both these features of their acoustic social interactions disappeared indicating that birds adapted their calling dynamics to cope with limited visual cues.

Objective analysis of vocal sequences using nested self-organizing maps

Traditional approaches to analyzing vocal sequences typically involve identifying individual sound units, labeling identified sounds, and describing the regularity of label sequences [A. Kershenbaum et al., “Acoustic sequences in non-human animals: A tutorial review and prospectus,” Biol. Rev. (2014)]. Although this method can provide useful information about the structure of sound sequences, the criteria for determining when distinct units have been successfully classified are often subjective and the temporal dynamics of sound generation are usually ignored. Self-organizing maps (SOMs) provide an alternative approach to classifying inputs that does not require subjective sorting or isolation of units. For instance, SOMs can be used to classify fixed duration frames sampled from recordings. Once an SOM has been trained to sort frames, the temporal structure of a vocal sequence can be analyzed by training a second SOM to sort spatiotemporal patterns of activation within the frame-sorting SOM. Analyzing humpback whale “song” using this technique revealed that: (1) perceptually warped spectra from frames varied uniformly along several continua; (2) a subset of frame patterns (sound types) was more prevalent; and (3) produced features varied systematically as a function of sequential position within a song for some sounds, but not others.

Sound production in the Ponto-Caspian goby Neogobius fluviatilis and acoustic affinities within the Gobius-lineage: implications for phylogeny

Event Abstract Back to Event Sound production in the Ponto-Caspian goby Neogobius fluviatilis and acoustic affinities within the Gobius-lineage: implications for phylogeny Stefano Malavasi1*, Sven Horvatić2, Francesco Cavraro1 and Davor Zanella2 1 University of Venice, Department of Environmental Sciences, Informatics and Statistics, Italy 2 University of Zagreb, Departmen of Zoology, Croatia The aim of this work is to provide the vocal repertoire of the Ponto-Caspian goby Neogobius fluviatilis and to compare the acoustical properties of this species with those of the other soniferous Mediterranean gobies belonging to the so called “Gobius-lineage”. Vocalisations and associated behaviours were recorded under controlled aquarium conditions in female and male Neogobius fluviatilis. Sound emission was elicited by means of “intruder tests”, using an individual of the same or of the opposite sex as intruder, and recording sounds by means of an hydrophone placed at few cm from the shelter, provided as a nest for the resident fish. Five acoustic properties, including spectral and temporal ones, were measured from 13 individuals. The vocal repertoire of the species consisted of sequences of short vocalizations during both agonistic and reproductive intraspecific interactions. The wave form of each sound resolves in a pure sine wave composed of rapidly repeated pulses. Sounds lasted about 200 ms, showing an average fundamental frequency of about 80 Hz (table 1). Sound properties did not differ between the reproductive and the aggressive contexts, being the general structure of the sounds highly stereotyped. Individual means of five acoustic properties characterising the sounds of seven species of the so called “Gobius” lineage, including Neogobius, were then entered in a Discriminant Function Analysis to assess how well species were differentiated on acoustic basis, and their degree of affinities. Results suggested that the pulse repetition rate of the sounds, that is the relative tonal/pulsatile nature of the sounds, is the most important property in differentiating species and that this property may contain a high level of phylogenetic signal, as the species producing tonal sounds are clustered together also according with the recent molecular phylogenies, available in the current literature. Results were also discussed in the light of the geological and phylogeographic events that are supposed to have driven the diversification of European gobies. Keywords: Gobies, acoustic properties, Messinian salinity crisis, Behavior, Pulse Rate Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Oral Presentation Topic: Phylogeny, Systematics and Genetics Citation: Malavasi S, Horvatić S, Cavraro F and Zanella D (2015). Sound production in the Ponto-Caspian goby Neogobius fluviatilis and acoustic affinities within the Gobius-lineage: implications for phylogeny. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00051 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 10 Nov 2015; Published Online: 10 Nov 2015. * Correspondence: Prof. Stefano Malavasi, University of Venice, Department of Environmental Sciences, Informatics and Statistics, Venice, Italy, mala@unive.it Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Stefano Malavasi Sven Horvatić Francesco Cavraro Davor Zanella Google Stefano Malavasi Sven Horvatić Francesco Cavraro Davor Zanella Google Scholar Stefano Malavasi Sven Horvatić Francesco Cavraro Davor Zanella PubMed Stefano Malavasi Sven Horvatić Francesco Cavraro Davor Zanella Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Reward associated with singing behavior correlates with opioid-related gene expression in the medial preoptic nucleus in male European starlings.

Birdsong consists of species-specific learned vocal sequences that are used primarily to attract mates and to repel competitors during the breeding season. However, many birds continue to sing at times when vocal production has no immediate or obvious impact on conspecific behavior. The mechanisms that ensure that animals produce important behaviors in contexts in which the function of these behaviors is not immediate or obvious are not known. One possibility is that animals engage in such behaviors because they are associated with pleasure. Here we examined the hypothesis that male European starlings sing outside of the breeding season in part because the act of singing in this context is facilitated and/or maintained by opioid-mediated reward. We measured song-associated reward using a conditioned place preference (CPP) test in male starlings producing fall, non-breeding season-typical song. We used quantitative real time PCR to measure expression of the enkephalin opioid precursor preproenkephalin (PENK) and mu opioid receptors (MOR) in the medial preoptic nucleus (POM; a region in which opioids are implicated in both reward and starling fall song) and additionally the song control region HVC as a control. Starlings developed a strong preference for a place that had been paired previously with the act of producing fall-typical song, indicating that fall song production was associated with a positive affective state. Both PENK and MOR mRNA expression in the POM, but not HVC, correlated positively with both individual reward state (as reflected in CPP) and undirected singing behavior. These results suggest that singing induces opioid receptor and enkephalin expression in the POM and consequent reward, and/or that opioid release in the POM induced by individual or environmental factors (e.g., the presence of food, safety of a flock or the absence of predators) induces a positive affective state which then facilitates singing behavior.

Phylogenetic reorganization of the basal ganglia: A necessary, but not the only, bridge over a primate Rubicon of acoustic communication

AbstractIn this response to commentaries, we revisit the two main arguments of our target article. Based on data drawn from a variety of research areas – vocal behavior in nonhuman primates, speech physiology and pathology, neurobiology of basal ganglia functions, motor skill learning, paleoanthropological concepts – the target article, first, suggests a two-stage model of the evolution of the crucial motor prerequisites of spoken language within the hominin lineage: (1) monosynaptic refinement of the projections of motor cortex to brainstem nuclei steering laryngeal muscles, and (2) subsequent “vocal-laryngeal elaboration” of cortico-basal ganglia circuits, driven by human-specific FOXP2 mutations. Second, as concerns the ontogenetic development of verbal communication, age-dependent interactions between the basal ganglia and their cortical targets are assumed to contribute to the time course of the acquisition of articulate speech. Whereas such a phylogenetic reorganization of cortico-striatal circuits must be considered a necessary prerequisite for ontogenetic speech acquisition, the 30 commentaries – addressing the whole range of data sources referred to – point at several further aspects of acoustic communication which have to be added to or integrated with the presented model. For example, the relationships between vocal tract movement sequencing – the focus of the target article – and rhythmical structures of movement organization, the connections between speech motor control and the central-auditory and central-visual systems, the impact of social factors upon the development of vocal behavior (in nonhuman primates and in our species), and the interactions of ontogenetic speech acquisition – based upon FOXP2-driven structural changes at the level of the basal ganglia – with preceding subvocal stages of acoustic communication as well as higher-order (cognitive) dimensions of phonological development. Most importantly, thus, several promising future research directions unfold from these contributions – accessible to clinical studies and functional imaging in our species as well as experimental investigations in nonhuman primates.

Acoustic sequences in non-human animals: a tutorial review and prospectus.

Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well-known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise-let alone understand-the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near-future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, 'Analysing vocal sequences in animals'. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial-style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality.

Animal vocal sequences: not the Markov chains we thought they were.

Many animals produce vocal sequences that appear complex. Most researchers assume that these sequences are well characterized as Markov chains (i.e. that the probability of a particular vocal element can be calculated from the history of only a finite number of preceding elements). However, this assumption has never been explicitly tested. Furthermore, it is unclear how language could evolve in a single step from a Markovian origin, as is frequently assumed, as no intermediate forms have been found between animal communication and human language. Here, we assess whether animal taxa produce vocal sequences that are better described by Markov chains, or by non-Markovian dynamics such as the 'renewal process' (RP), characterized by a strong tendency to repeat elements. We examined vocal sequences of seven taxa: Bengalese finches Lonchura striata domestica, Carolina chickadees Poecile carolinensis, free-tailed bats Tadarida brasiliensis, rock hyraxes Procavia capensis, pilot whales Globicephala macrorhynchus, killer whales Orcinus orca and orangutans Pongo spp. The vocal systems of most of these species are more consistent with a non-Markovian RP than with the Markovian models traditionally assumed. Our data suggest that non-Markovian vocal sequences may be more common than Markov sequences, which must be taken into account when evaluating alternative hypotheses for the evolution of signalling complexity, and perhaps human language origins.

Fin whale vocalization classification and abundance estimation

Several thousand fin whale vocalizations from multiple fin individuals were passively recorded by a high-resolution coherent hydrophone array system in the Gulf of Maine in Fall 2006. The recorded fin whale vocalizations have relatively short durations roughly 0.4 s and frequencies ranging from 15 to 40 Hz. Here we classify the fin whale vocalizations and apply the results to estimate the minimum number of vocalizing fin individuals detected by our hydrophone array. The horizontal azimuth or bearing of each fin whale vocalization is first determined by beamforming. Each beamformed fin whale vocalization spectrogram is next characterized by several features such as center frequency, upper and lower frequency limits, as well as amplitude-weighted mean frequency. The vocalizations are then classified using k-mean clustering into several distinct vocal types. The vocalization clustering result is then combined with the bearing-time trajectory information for a consecutive sequence of vocalizations to provide an estimate of the minimum number of vocalizing fin individuals detected.

Fin whale song characteristics recorded on ocean bottom seismometers in the Northeast Pacific Ocean

Fin whales produce low frequency sequences of vocalizations that can be detected opportunistically on ocean bottom seismometers (OBSs). Using an automatic detection algorithm, we have analyzed fin whale calls recorded on OBSs in the Northeast Pacific Ocean over broad spatial and temporal scales. The Cascadia Initiative experiment consists of 70 OBSs deployed for a total of four years (2011–2015). It extends from Vancouver Island to Cape Mendocino, and several hundred kilometers offshore. Additional OBS data that overlap spatially with the northern portion of the Cascadia Initiative instruments are available from the Neptune Canada cabled observatory, which has been online since 2009, and from standalone deployments between 2003 and 2006. With this study, we examine call characteristics and seasonal call counts for patterns that might indicate migratory movements or distinct acoustic populations. Both frequency and inter-pulse interval (IPI) are automatically extracted for each detected call and seasonal and inter-annual calling patterns are examined using daily binned call count histograms. Preliminary analysis of a subset of Cascadia Initiative data from 2011 to 2013 shows a dominant sequence of alternating classic and backbeat calls at center frequencies of 20 and 18.5 Hz, respectively, and preceding IPIs of 16 and 18 s, respectively.

Fundamentos de fonología y fonética española para hablantes de inglés: Manual práctico de español como lengua extranjera by Eva Núñez Méndez (review)

Reviewed by: Fundamentos de fonología y fonética española para hablantes de inglés: Manual práctico de español como lengua extranjeraby Eva Núñez Méndez Nate Maddux Núñez Méndez, Eva. Fundamentos de fonología y fonética española para hablantes de inglés: Manual práctico de español como lengua extranjera. 2nded. Muenchen: LINCOM, 2012. Pp. 132. ISBN 978-3-8958-6958-7. In a market saturated with introductory Spanish phonetics and phonology texts that ignore the language background of the reader, Núñez Méndez’s book responds to a need for pedagogical resources designed with the native English speaker in mind. The nine-chapter volume has two stated goals: to assist advanced-level anglophone learners of Spanish in their pronunciation of the sounds that typify the language across its regional varieties, and to give readers a clear understanding of the articulatory characteristics of these sounds so that they may be faithfully reproduced. The first three chapters provide a general orientation to human language and the field of linguistics and its subdisciplines. The introductory chapter lays out the primary objectives of linguistics and offers an overview of the subdisciplines and methodological orientations within the field. Chapter 2 defines Language ( lenguaje) and gives a snapshot of the world’s language families. The third chapter begins with a chronological account of the emergence of historical, descriptive, and generative linguistics as fields of inquiry. Neurolinguistics, language processing and speech production are also given brief mention in the third chapter. The portion of the book dedicated to the sounds of Spanish commences with chapter 4, which surveys the orthography and phoneme-grapheme correspondences of the language before moving on to stress assignment, permissible syllable structures, treatment of vocalic sequences, resyllabification rules, and intonation patterns of various sentence types in Spanish. A definition of phonology and an explanation of the contrastive function and distributive properties of Spanish phonemes form the basis of the fifth chapter. Chapter 6 provides an overview of human articulatory anatomy, a classification of consonants by manner and place of articulation, the fundamental characteristics of Spanish vocoids, and a discussion of allophonic variation and nasal assimilation processes in Spanish. Students of language variation will likely find chapters 7 and 8 to be most valuable. The seventh chapter considers regional variation and its primary manifestations in Spanish, differentiating the stereotypically Castilian realizations of the palatal lateral and voiceless interdental fricative with their phonemic counterparts in Andalusian and American varieties of the language. Within this context of variation, Núñez Méndez describes a number of phonological processes, and it is here she introduces the conventions of phonetic transcription. Chapter 8 lays out the main principles of Spanish dialectology, social and contextual approaches to variation, regional linguistic norms, and language contact. The chapter concludes with a discussion of Spanish in the United States, focusing on lexical loans, calques, slang and code-switching. The ninth chapter is an applied section that takes an itemized approach to explaining how the Spanish phonemes most problematic for anglophones, such as the unaspirated voiceless plosives, the voiceless velar fricative, and the bipartite system of rhotics, differ in articulation from their approximate equivalents in English. The chapter also compares syllabic rhythm and intonation patterns between the languages, with the intention of facilitating the acquisition of these suprasegmental features by native English speakers. Accompanying the six-page glossary of key terms and three pages of bibliography offered at the conclusion of the manual is an appendix that will prove valuable to advanced-level students with an interest in broadening the scope of their study of Spanish phonetics and phonology beyond the text. The section offers a table of the allophonic variants of the Spanish vocalic inventory, a chart of the Spanish phonemic inventory organized by manner and place of articulation, and a detailed comparison of the phonetic symbols used to represent the sounds of Spanish according to both the International Phonetic Alphabet (IPA) and Revista de Filología Española (RFE). What sets Núñez Méndez’s book apart as a unique and important resource for English-speaking students of Spanish phonetics and phonology, in addition to the...

Accurate glottal model parametrization by integrating audio and high-speed endoscopic video data

The aim of this paper is to evaluate the effectiveness of using video data for voice source parametrization in the representation of voice production through physical modeling. Laryngeal imaging techniques can be effectively used to obtain vocal fold video sequences and to derive time patterns of relevant glottal cues, such as folds edge position or glottal area. In many physically based numerical models of the vocal folds, these parameters are estimated from the inverse filtered glottal flow waveform, obtained from audio recordings of the sound pressure at lips. However, this model inversion process is often problematic and affected by accuracy and robustness issues. It is here discussed how video analysis of the fold vibration might be effectively coupled to the parametric estimation algorithms based on voice recordings, to improve accuracy and robustness of model inversion.

Entropy rate as a measure of animal vocal complexity

Vocal complexity is an important concept for investigating the role and evolution of animal communication and sociality. However, no one definition of ‘complexity’ appears to be appropriate for all uses. Repertoire size has been used to quantify complexity in many bird and some mammalian studies, but is impractical in cases where vocalizations are highly diverse, and repertoire size is essentially non-limited at realistic sample sizes. Some researchers have used information-theoretic measures such as Shannon entropy, to describe vocal complexity, but these techniques are descriptive only, as they do not address hypotheses of the cognitive mechanisms behind vocal signal generation. In addition, it can be shown that simple measures of entropy, in particular, do not capture syntactic structure. In this work, I demonstrate the use of an alternative information-theoretic measure, the Markov entropy rate, which quantifies the diversity of transitions in a vocal sequence, and thus is capable of distinguishing sequences with syntactic structure from those generated by random, statistically independent processes. I use artificial sequences generated from different stochastic mechanisms, as well as real data from the vocalizations of the rock hyrax Procavia capensis, to show how different complexity metrics scale differently with sample size. I show that entropy rate provides a good measure of complexity for Markov processes and converges faster than repertoire size estimates, such as the Lempel–Ziv metric. The commonly used Shannon entropy performs poorly in quantifying complexity.