question: How is it that every human has a unique voice?
comment: It's not just vocal cord length. It's nasal passages, jaw structure, bone density. So many things play into the tone of peoples voices.
passages: The sound of each individual's voice is entirely unique not only because of the actual shape and size of an individual's vocal cords but also due to the size and shape of the rest of that person's body, especially the vocal tract, and the manner in which the speech sounds are habitually formed and articulated. (It is this latter aspect of the sound of the voice that can be mimicked by skilled performers.) Humans have vocal folds that can loosen, tighten, or change their thickness, and over which breath can be transferred at varying pressures. The shape of chest and neck, the position of the tongue, and the tightness of otherwise unrelated muscles can be altered. Any one of these actions results in a change in pitch, volume, timbre, or tone of the sound produced. Sound also resonates within different parts of the body, and an individual's size and bone structure can affect somewhat the sound produced by an individual.
   BULLET::::- Independent convergent evolution: All three avian groups evolved vocal learning and similar neural pathways independently (not through a common ancestor). This suggests that there are strong epigenetic constraints imposed by the environment or morphological needs, and so this hypothesis predicts that groups that newly evolve vocal learning will also develop similar neural circuits.
   Section::::Physiology and vocal timbre.:Vocal registration.
   The ability to vary the ab/adduction of the vocal folds quickly has a strong genetic component, since vocal fold adduction has a life-preserving function in keeping food from passing into the lungs, in addition to the covering action of the epiglottis. Consequently, the muscles that control this action are among the fastest in the body. Children can learn to use this action consistently during speech at an early age, as they learn to speak the difference between utterances such as "apa" (having an abductory-adductory gesture for the p) as "aba" (having no abductory-adductory gesture). Surprisingly enough, they can learn to do this well before the age of two by listening only to the voices of adults around them who have voices much different from their own, and even though the laryngeal movements causing these phonetic differentiations are deep in the throat and not visible to them.
   Section::::Genetic applications to humans.
   Section::::Evidence of vocal learning in various species.:Controversial or limited vocal learners.:Mice.
  
  Mice produce long sequences of vocalizations or "songs" that are used for both isolation calls in pups when cold or removed from nest and for courtship when males sense a female or detect pheromones in their urine. These ultrasonic vocalizations consist of discrete syllables and patterns, with species-specific differences. Males tend to use particular syllable types that can be used to differentiate individuals.
   The vocal folds, in combination with the articulators, are capable of producing highly intricate arrays of sound. The tone of voice may be modulated to suggest emotions such as anger, surprise, fear, happiness or sadness. The human voice is used to express emotion, and can also reveal the age and sex of the speaker. Singers use the human voice as an instrument for creating music.
  
  Section::::Voice types and the folds (cords) themselves.
   In primates, only humans are known to be capable of complex vocal learning. Similar to the first hypothesis relating to birds, one explanation is that vocal learning evolved independently in humans. An alternative hypothesis suggests evolution from a primate common ancestor capable of vocal learning, with the trait subsequently being lost at least eight other times. Considering the most parsimonious analysis, it seems unlikely that the number of independent gains (one in humans) would be exceeded so greatly by the number of independent losses (at least eight), which supports the independent evolution hypothesis.
  
  Section::::Neurobiology.
  
  Section::::Neurobiology.:Neural pathways in avian vocal learners.
   Section::::Conception and creation.:Voice.
   Section::::Voice modulation in spoken language.
  
  Human spoken language makes use of the ability of almost all people in a given society to dynamically modulate certain parameters of the laryngeal voice source in a consistent manner. The most important communicative, or phonetic, parameters are the voice pitch (determined by the vibratory frequency of the vocal folds) and the degree of separation of the vocal folds, referred to as vocal fold adduction (coming together) or abduction (separating).
   Vocal learning phenotype also differ within groups and closely related species will not display the same abilities. Within avian vocal learners, for example, zebra finch songs only contain strictly linear transitions that go through different syllables in a motif from beginning to end, yet mockingbird and nightingale songs show element repetition within a range of legal repetitions, non-adjacent relationships between distant song elements, and forward and backward branching in song element transitions. Parrots are even more complex as they can imitate the speech of heterospecifics like humans and synchronize their movements to a rhythmic beat.
  
  Section::::Classification.:Continuum hypothesis.
   There are seven areas that may be listed as possible vocal resonators. In sequence from the lowest within the body to the highest, these areas are the chest, the tracheal tree, the larynx itself, the pharynx, the oral cavity, the nasal cavity, and the sinuses.
  
  Section::::Influences of the human voice.
   The twelve-tone musical scale, upon which a large portion of all music (western popular music in particular) is based, may have its roots in the sound of the human voice during the course of evolution, according to a study published by the New Scientist. Analysis of recorded speech samples found peaks in acoustic energy that mirrored the distances between notes in the twelve-tone scale.
  
  Section::::Voice disorders.
   Additionally, it has been suggested that due to the overlap of FOXP1 and FOXP2 expression in songbirds and humans, mutations in FOXP1 may also result in speech and language abnormalities seen in individuals with mutations in FOXP2.
  
  These genetic links have important implications for studying the origin of language because FOXP2 is so similar among vocal learners and humans, as well as important implications for understanding the etiology of certain speech and language disorders in humans.
  
  Currently, no other genes have been linked as compellingly to vocal learning in animals or humans.
  
  Section::::See also.
  
  BULLET::::- Animal cognition
  
  BULLET::::- Bioacoustics
   Singers can also learn to project sound in certain ways so that it resonates better within their vocal tract. This is known as vocal resonation. Another major influence on vocal sound and production is the function of the larynx, which people can manipulate in different ways to produce different sounds. These different kinds of laryngeal function are described as different kinds of vocal registers. The primary method for singers to accomplish this is through the use of the Singer's Formant, which has been shown to be a resonance added to the normal resonances of the vocal tract above the frequency range of most instruments and so enables the singer's voice to carry better over musical accompaniment.
   The syrinx is the sound-producing vocal organ of birds, located at the base of a bird's trachea. As with the mammalian larynx, sound is produced by the vibration of air flowing across the organ. The syrinx enables some species of birds to produce extremely complex vocalizations, even mimicking human speech. In some songbirds, the syrinx can produce more than one sound at a time.
  
  Section::::Respiratory system.:Circulatory system.
   BULLET::::- Thurman, Leon & Welch, ed., Graham (2000), Bodymind & voice: Foundations of voice education (revised ed.), Collegeville, Minnesota: The VoiceCare Network et al.,
  
  Section::::External links.
  
  BULLET::::- Free Voice analyzer and Biometrics displaying software from University College London
  
  BULLET::::- The Head Voice and Other Problems, 1917, by D. A. Clippinger, from Project Gutenberg
  
  BULLET::::- The Voice Foundation's official website
  
  BULLET::::- The Anatomy of Singing
  
  BULLET::::- David Harper, vocal coach: A passion for the voice that never wanes – Opera article
  
  BULLET::::- Irish Voice festival official website
  
  BULLET::::- How the voice works – "The Voice Works Like a Car"
   Historically, species have been classified into the binary categories of vocal learner or vocal non-learner based on their ability to produce novel vocalizations or imitate other species, with evidence from social isolation, deafening studies, and cross-fostering experiments. However, vocal learners exhibit a great deal of plasticity or variation between species, resulting in a spectrum of ability. The vocalizations of songbirds and whales have a syntactic-like organization similar to that of humans but are limited to Finite-State Grammars (FSGs), where they can generate strings of sequences with limited structural complexity. Humans, on the other hand, show deeper hierarchical relationships, such as the nesting of phrases within others, and demonstrate compositional syntax, where changes in syntactic organization generate new meanings, both of which are beyond the capabilities of other vocal learning groups
   Section::::Evidence of vocal learning in various species.:Known vocal learners.:Cetaceans.
  
  Section::::Evidence of vocal learning in various species.:Known vocal learners.:Cetaceans.:Whales.
  
  Male humpback whales ("Megaptera novaeangliae") sing as a form of sexual display while migrating to and from their breeding grounds. All males in a population produce the same song which can change over time, indicating vocal learning and cultural transmission, a characteristic shared by some bird populations. Songs become increasingly dissimilar over distance and populations in different oceans have dissimilar songs.
   BULLET::::- Common ancestor: This alternative hypothesis suggests that vocal learning birds evolved the trait from a distant common ancestor, which was then lost four independent times in interrelated vocal non-learners. Possible causes include high survival costs of vocal learning (predation) or weak adaptive benefits that did not induce strong selection for the trait for organisms in other environments.
   Section::::Evidence of vocal learning in various species.
  
  Section::::Evidence of vocal learning in various species.:Known vocal learners.
  
  Section::::Evidence of vocal learning in various species.:Known vocal learners.:Birds.
  
  The most extensively studied model organisms of vocal learning are found in birds, namely songbirds, parrots, and hummingbirds. The degree of vocal learning in each specific species varies. While many parrots and certain songbirds like canaries can imitate and spontaneously combine learned sounds during all periods of their life, other songbirds and hummingbirds are limited to a certain songs learned during their critical period.
  
  Section::::Evidence of vocal learning in various species.:Known vocal learners.:Bats.
   Currently, there are two competing models that elucidate the role of LMAN in generating an instructive error signal and projecting it to the motor production pathway:
  
  BULLET::::- "Bird's own song (BOS)-tuned error correction model"
  
  BULLET::::- "Efference copy model of error correction"
   Section::::Cultural impact.
   The young of some birds learn to communicate vocally by social learning, imitating their parents, as well as the dominant birds of their flock. Lacking vocal cords, birds are thought to make tones and sounds using throat muscles and membranes – the syrinx in particular. There are likely to be limitations on the sounds that birds can mimic due to differences in anatomical structures, such as their lacking lips. However, it has been suggested that mimicry amongst birds is almost ubiquitous and it is likely that eventually, all species will be shown to be able to have some ability to mimic extra-specific sounds (but not necessarily human speech).
   Section::::Cast.
  
  BULLET::::- Fatou N'Diaye - Vita
  
  BULLET::::- Ângelo Torres - Yano
  
  BULLET::::- Jean-Christophe Dollé - Pierre
  
  BULLET::::- Bia Gomes - Vita's mother
  
  BULLET::::- Jorge Biague -Mito
  
  BULLET::::- José Carlos Imbombo -Caminho
  
  BULLET::::- François Hadji-Lazaro - Bjorn
  
  BULLET::::- Danielle Evenou - mother of Pierre
  
  BULLET::::- Bonnafet Tarbouriech - father of Pierre
  
  BULLET::::- Maica Baio
  
  Section::::Production.
  