Speech is the vocalized form of communication used by humans and some
animals, which is based upon the syntactic combination of items drawn
from the lexicon. Each spoken word is created out of the phonetic
combination of a limited set of vowel and consonant speech sound units
(phonemes). These vocabularies, the syntax that structures them, and
their sets of speech sound units differ, creating many thousands of
different, and mutually unintelligible, human languages. The vocal
abilities that enable humans to produce speech also enable them to
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
written language, often one that differs in its vocabulary, syntax and
phonetics from its associated spoken one, a situation called
diglossia. In addition to its use in communication, it is suggested by
some psychologists such as
Lev Vygotsky that speech is internally used
in 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 recreate them, which plays a key role in
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 animals
also communicate with vocalizations. While none in the wild have
comparably 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 evolutionary
origins of speech are unknown and subject to much debate and
4 Problems involving speech
5.1 The classical model
5.2 Modern research
6 See also
8 Further reading
9 External links
Speech production and Linguistics
Speech production is a multi-step process by which thoughts are
generated into spoken utterances. Production involves the selection of
appropriate words and the appropriate form of those words from the
lexicon and morphology, and the organization of those words through
the syntax. Then, the phonetic properties of the words are retrieved
and the sentence is uttered through the articulations associated with
those phonetic properties.
In linguistics (articulatory phonetics), articulation refers to how
the tongue, lips, jaw, vocal cords, and other speech organs used to
produce sounds are used to make sounds.
Speech sounds are categorized
by manner of articulation and place of articulation. Place of
articulation refers to where the airstream in the mouth is
Manner of articulation
Manner of articulation refers to the manner in which the
speech organs interact, such as how closely the air is restricted,
what form of airstream is used (e.g. pulmonic, implosive, ejectives,
and clicks), whether or not the vocal cords are vibrating, and whether
the nasal cavity is opened to the airstream. The concept is
primarily used for the production of consonants, but can be used for
vowels in qualities such as voicing and nasalization. For any place of
articulation, there may be several manners of articulation, and
therefore several homorganic consonants.
Normal human speech is pulmonic, produced with pressure from the
lungs, which creates phonation in the glottis in the larynx, which is
then modified by the vocal tract and mouth 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 (better
known as Donald Duck talk).
Speech production is a complex activity, and as a consequence errors
are common, especially in children.
Speech errors come in many forms
and are often used to provide evidence to support hypotheses about the
nature of speech. As a result, speech errors are often used in the
construction of models for language production and child language
acquisition. For example, the fact that children often make the error
of over-regularizing the -ed past tense suffix in English (e.g. saying
'singed' instead of 'sang') shows that the regular forms are acquired
Speech errors associated with certain kinds of aphasia
have been used to map certain components of speech onto the brain and
see the relation between different aspects of production: for example,
the difficulty of expressive aphasia patients in producing regular
past-tense verbs, but not irregulars like 'sing-sang' has been used to
demonstrate that regular inflected forms of a word are not
individually stored in the lexicon, but produced from affixation of
the base form.
Speech perception refers to the processes by which humans can
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
listeners recognize speech sounds and use this information to
understand spoken language. Research into speech perception also has
applications in building computer systems that can recognize speech,
as well as improving speech recognition for hearing- and
Speech perception is categorical, in that people put the sounds they
hear into categories rather than perceiving them as a spectrum. People
are more likely to be able to hear differences in sounds across
categorical boundaries than within them. A good example of this is
voice onset time (VOT). For example, Hebrew speakers, who distinguish
voiced /b/ from voiceless /p/, will more easily detect a change in VOT
from -10 ( perceived as /b/ ) to 0 ( perceived as /p/ ) than a change
in VOT from +10 to +20, or -10 to -20, despite this being an equally
large change on the VOT spectrum.
In speech repetition, speech being heard is quickly turned from
sensory input into motor instructions needed for its immediate or
delayed vocal imitation (in phonological memory). This type of mapping
plays a key role in enabling children to expand their spoken
vocabulary. Masur (1995) found that how often children repeat novel
words versus those they already have in their lexicon is related to
the size of their lexicon later on, with young children who repeat
more novel words having a larger lexicon later in development. Speech
repetition could help facilitate the acquisition of this larger
Problems involving speech
See also: Speech-language pathology
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 (bronchitis), 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 (as opposed to the actual sound) leads to
poor speech production.
Hearing problems, such as otitis media with effusion, and listening
problems, auditory processing disorders, can lead to phonological
Articulatory problems, such as slurred speech, stuttering, lisping,
cleft palate, ataxia, or nerve damage leading to problems in
Tourette syndrome and tics can also affect speech.
Various congenital and acquired tongue diseases can affect speech as
can motor neuron disease.
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
The classical model
Broca's and Wernicke's areas.
The classical or Wernicke-Geschwind model of the language system in
the brain focuses on
Broca's area in the inferior prefrontal cortex,
Wernicke's area in the posterior superior temporal gyrus on the
dominant hemisphere of the brain (typically the left hemisphere for
language). In this model, a linguistic auditory signal is first sent
from the auditory cortex to Wernicke's area. The lexicon is accessed
in Wernicke's area, and these words are sent via the arcuate
fasciculus to Broca's area, where morphology, syntax, and instructions
for articulation are generated. This is then sent from
Broca's area to
the motor cortex for articulation.
Paul Broca identified an approximate region of the brain in 1861
which, when damaged in two of his patients, caused severe deficits in
speech production, where his patients were unable to speak beyond a
few monosyllabic words. This deficit, known as Broca's or expressive
aphasia, is characterized by difficulty in speech production where
speech is slow and labored, function words are absent, and syntax is
severely impaired, as in telegraphic speech. In expressive aphasia,
speech comprehension is generally less affected except in the
comprehension of grammatically complex sentences. Wernicke's area
is named after Carl Wernicke, who in 1874 proposed a connection
between damage to the posterior area of the left superior temporal
gyrus and aphasia, as he noted that not all aphasic patients had
suffered damage to the prefrontal cortex. Damage to Wernicke's
area produces Wernicke's or receptive aphasia, which is characterized
by relatively normal syntax and prosody but severe impairment in
lexical access, resulting in poor comprehension and nonsensical or
Modern models of the neurological systems behind linguistic
comprehension and production recognize the importance of Broca's and
Wernicke's areas, but are not limited to them nor solely to the left
hemisphere.  Instead, multiple streams are involved in speech
production and comprehension. Damage to the left lateral sulcus has
been connected with difficulty in processing and producing morphology
and syntax, while lexical access and comprehension of irregular forms
(e.g. eat-ate) remain unaffected.
Freedom of speech
Freedom of speech portal
Freedom of speech
Index of linguistics articles
List of language disorders
Spatial hearing loss
^ Levelt, Willem J. M. (1999). "Models of word production". Trends in
Cognitive Sciences. 3 (6): 223–232.
^ Catford, J.C.; Esling, J.H. (2006). "Articulatory Phonetics". In
Brown, Kieth. Encyclopedia of
Linguistics (2nd ed.).
Amsteram: Elsevier Science. pp. 425–442.
^ Fromkin, Victoria (1973). "Introduction".
Speech Errors as
Linguistic Evidence. The Hague: Mouton. pp. 11–46.
^ Plunkett, Kim; Juola, Patrick (1999). "A connectionist model of
english past tense and plural morphology". Cognitive Science. 23 (4):
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Past Tense Morphemes in English and French: Evidence From Bilingual
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^ Ullman, Michael T.; et al. (2005). "Neural correlates of lexicon and
grammar: Evidence from the production, reading, and judgement of
inflection in aphasia".
Brain and Language. 93: 185–238.
^ Kennison, Shelia (2013). Introduction to
Language Development. Los
^ Kishon-Rabin, Liat; Rotshtein, Shira; Taitelbaum, Riki (2002).
"Underlying Mechanism for Categorical Perception: Tone-Onset Time and
Voice-Onset Time Evidence of Hebrew Voicing". Journal of Basic and
Clinical Physiology and Pharmacology. 13 (2): 117–134.
^ Masur, Elise (1995). "Infants' Early Verbal Imitation and Their
Later Lexical Development". Merrill-Palmer Quarterly. 41 (3):
^ Kertesz, A. (2005). "Wernicke--GeschwindModel". In L. Nadel,
Encyclopedia of cognitive science. Hoboken, NJ: Wiley.
^ a b Hillis, A. E., & Caramazza, A. (2005). "Aphasia". In L.
Nadel, Encyclopedia of cognitive science. Hoboken, NJ: Wiley.
^ Wernicke K. (1995). "The aphasia symptom-complex: A psychological
study on an anatomical basis (1875)". In Paul Eling. Reader in the
History of Aphasia: From sasi(Franz Gall to). 4. Amsterdam: John
Benjamins Pub Co. pp. 69–89. ISBN 90-272-1893-5.
^ Nakai, Y; Jeong, JW; Brown, EC; Rothermel, R; Kojima, K; Kambara, T;
Shah, A; Mittal, S; Sood, S; Asano, E (2017). "Three- and
four-dimensional mapping of speech and language in patients with
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PMID 28334963. CS1 maint: display-authors (link)
^ Tyler, Lorraine K.; Marslen-Wilson, William (2009). "Fronto-temporal
brain systems supporting spoken language comprehension". In Moore,
Brian C. J.; Tyler, Lorraine K.; Marslen-Wilson, William D. The
Perception of Speech: from sound to meaning. Oxford: Oxford University
Press. pp. 193–217. ISBN 978-0-19-956131-5.
(in French) Fitzpatrick, Élizabeth M. Apprendre à écouter et à
parler. University of Ottawa Press, 2013. Available at Project MUSE.
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Symptoms and signs:
Speech and voice / Symptoms involving head and
neck (R47–R49, 784)
Transcortical sensory aphasia
Transcortical motor aphasia
Mixed transcortical aphasia
Progressive nonfluent aphasia
Logopenic progressive aphasia
Developmental verbal dyspraxia/
Apraxia of speech
Auditory verbal agnosia
Specific language impairment
Pressure of speech
Developmental coordination disorder/Apraxia
Auditory processing disorder
Hypersensitive gag reflex
History of communication
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Philosophy of language
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