Speech is the vocalized form of human communication.
It is based upon the syntactic combination of lexicals and names that are drawn from
very large vocabularies.
Each spoken word is created out of the phonetic combination of a limited set of vowel and
consonant speech sound units.
These vocabularies, the syntax which structures them, and their set of speech sound units
differ, creating the existence of many thousands of different types of mutually unintelligible
human languages.
Most human speakers are able to communicate in two or more of them, hence being polyglots.
The vocal abilities that enable humans to produce speech also provide humans with the
ability to sing.
A gestural form of human communication exists for the deaf in the form of sign language.
Speech in some cultures has become the basis of a written language, often one that differs
in its vocabulary, syntax and phonetics from its associated spoken one, a situation called
diglossia.
Speech in addition to its use in communication, it is suggested by some psychologists such
as Vygotsky is internally used by mental processes to enhance and organize cognition in the form
of an interior monologue.
Speech is researched in terms of the speech production and speech perception of the sounds
used in vocal language.
Other research topics concern speech repetition, the ability to map heard spoken words into
the vocalizations needed to recreated that plays a key role in the vocabulary expansion
in children and speech errors.
Several academic disciplines study these including acoustics, psychology, speech pathology, linguistics,
cognitive science, communication studies, otolaryngology and computer science.
Another area of research is how the human brain in its different areas such as the Broca's
area and Wernicke's area underlies speech.
It is controversial how far human speech is unique in that other animals also communicate
with vocalizations.
While none in the wild have compatibly large vocabularies, research upon the nonverbal
abilities of language trained apes such as Washoe and Kanzi raises the possibility that
they might have these capabilities.
The origins of speech are unknown and subject to much debate and speculation.
Production
In linguistics, manner of articulation describes how the tongue, lips, jaw, and other speech
organs are involved in making a sound make contact.
Often the concept is only used for the production of consonants.
For any place of articulation, there may be several manners, and therefore several homorganic
consonants.
Normal human speech is produced with pulmonary pressure provided by the lungs which creates
phonation in the glottis in the larynx that is then modified by the vocal tract into different
vowels and consonants.
However humans can pronounce words without the use of the lungs and glottis in alaryngeal
speech of which there are three types: esophageal speech, pharyngeal speech and buccal speech.
Perception
Speech perception refers to the processes by which humans are able to interpret and
understand the sounds used in language.
The study of speech perception is closely linked to the fields of phonetics and phonology
in linguistics and cognitive psychology and perception in psychology.
Research in speech perception seeks to understand how human listeners recognize speech sounds
and use this information to understand spoken language.
Speech research has applications in building computer systems that can recognize speech,
as well as improving speech recognition for hearing- and language-impaired listeners.
Repetition
Spoken vocalizations are quickly turned from sensory inputs into motor instructions needed
for their immediate or delayed vocal imitation.
This occurs independently of speech perception.
This mapping plays a key role in enabling children to expand their spoken vocabulary
and hence the ability of human language to transmit across generations.
Errors
Speech is a complex activity; as a result, errors are often made in speech.
Speech errors have been analyzed by scientists to understand the nature of the processes
involved in the production of speech.
Problems involving speech
There are several organic and psychological factors that can affect speech.
Among these are: Diseases and disorders of the lungs or the
vocal cords, including paralysis, respiratory infections, vocal fold nodules and cancers
of the lungs and throat.
Diseases and disorders of the brain, including alogia, aphasias, dysarthria, dystonia and
speech processing disorders, where impaired motor planning, nerve transmission, phonological
processing or perception of the message leads to poor speech production.
Hearing problems, such as otitis media with effusion, and listening problems, auditory
processing disorders, can lead to phonological problems.
Articulatory problems, such as slurred speech, stuttering, lisping, cleft palate, ataxia,
or nerve damage leading to problems in articulation.
Tourette syndrome and tics can also affect speech.
In addition to dysphasia, anomia and auditory processing disorder can impede the quality
of auditory perception, and therefore, expression.
Those who are Hard of Hearing or deaf may be considered to fall into this category.
Brain physiology
Two areas of the cerebral cortex are necessary for speech.
Broca's area, named after its discoverer, French neurologist Paul Broca, is in the frontal
lobe, usually on the left, near the motor cortex controlling muscles of the lips, jaws,
soft palate and vocal cords.
When damaged by a stroke or injury, comprehension is unaffected but speech is slow and labored
and the sufferer will talk in "telegramese".
Wernicke's area, discovered in 1874 by German neurologist Carl Wernicke, lies to the back
of the temporal lobe, again, usually on the left, near the areas receiving auditory and
visual information.
Damage to it destroys comprehension - the sufferer speaks fluently but nonsensically.
Some researchers have explored the connections between brain physiology, neuroscience, and
other elements of physiology to that of communication.
Communibiology first proposed by Beatty and McCroskey address these issues and presents
a set of specific axioms about these phenomena.
See also
Freedom of speech FOXP2
Imagined speech Index of linguistics articles
Spatial hearing loss Speechwriter
Talking birds Vocology
References
Further reading (French) Fitzpatrick, Élizabeth M. Apprendre
à écouter et à parler.
University of Ottawa Press, 2013.
Available at Project MUSE.
External links Acoustic measures of speech, www.speech-therapy-information-and-resources.com
Speaking captured by real-time MRI, YouTube