Download Speech and Language

Speech and Language
Dr Derakhshandeh, PhD
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Thinking and Language
Language is the ability to encode ideas into
signals for communication
Nothing is more human than
speech
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Language is the most complex
everyday human behavior
• 100 muscles work at any given time for
speech
• For each of these there are about 100
nerve endings
• We produce 14 sounds per second
• (100 x 100 x 14=140,000 nerve-to-muscle
events each second of conversational
speech
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How complex? …linguistic
knowledge
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• more than 6,000 languages exist
• it is incomprehensible to suggest:
language could be viewed as
some sort of simple, clear-cut addition
to human physiology made possible
by an enlarged brain unique to Homo
sapiens
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The central ideas of evolution
• The life has a history
• Changed over time
• Different species share common
ancestors
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DNA (deoxyribonucleic acid)
• DNA is the double-stranded
molecule that contains the genetic
code
• Jared Diamond suggests:
–the amount of DNA similarity is
a key indicator of the closeness
to other primates, esp., the
Bonobos
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Almost us!
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• Common and pygmy chimps differ in 0.7%
DNA
»Gorillas differ in 2.3%
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• Humans and chimps differ in 1.6% (98.4%
the same)
• Gorillas separated from chimps before
humans did
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DNA
• One of the ways we
determine closeness with
other primates
• Closest primates are:
– Bonobo (pygmy)
– chimpanzees
– Gorilla
– Orangutan
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the genetic distances between Hominoids
Chimpanzees are actually closer to humans genetically than
to Orangutans and the same genetic distance from Gorillas
Orangutans are the most different from humans genetically
yet relatively closer to Chimpanzees
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Hominoids
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A polygenetic or
monogenetic linguistic origin?
• Monogenesis?
–A single location from which all humans
emerged
• Polygenesis?
–More than one location
–but similar development in each site
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Speech begins… When?
• By at least 30,000 years ago:
– humans speech was fully modern
• Begins between Australopithecines and
Homo habilus (between 4M B.P. and
700,000B.P.)
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Were there other human species?
• Homo habilis
• About 5 foot tall
• average brain size 650cc, much
larger than Australopithecines
• Brain organization may have included
an area for speech (Broca's area)
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H. habilis
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Australopithecus afarensis
• 3.5 to 4 foot tall, known as "Lucy“
• Pelvis and legs more like humans but
skull chimp like
• Protruding mouth, small brained,
canines project slightly
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One possible relationship to
other hominids
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Basic biological aspects of
human language:
Brain
Cerebral
Left hemisphere
Corpus callosum
Neo-Cortex
Broca’s Area
Wernicke’s Area
Angular Gyrus
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Comprehension of
speech
Controls the muscles
of the lips, jaw,
tongue, vocal cord,…
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Basic biological aspects of
human language: Voice Box
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Hyoid Bone
Larynx
Trachea
Tongue
Oral/Nasal Cavity
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Voice Box
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Sound
• Sound is produced when air flowing from the
lungs passes into the voice box
• through the gap made by the vocal cords,
which open and close like a valve
• During speech, the vocal cords vibrate as air
passes through them
• releasing a rapid series of puffs into the vocal
tract
• determines the pitch of a person's voice
• the faster the rate, the higher the pitch
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Sound systems
• The human upper respiratory tract made
speech possible
• as the high larynx seen in species like the
chimp dropped
• creating an expanded pharynx in human
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Sound systems
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Unfortunately:
"speech does not fossilize"
• notes anthropologist John Shea of the
State University of New York:
• Writing appears 6000 years ago
• there is scant evidence for the
existence of notation before 13,000
years ago
• How long might LANGUAGE have
been around before that?
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Fossils: the brain capacity
• Is raw for complex LANGUAGE
• with the necessary mouth and throat anatomy
• were probably in place before 150,000 years
ago
• But most of the behaviors thought to depend on
LANGUAGE did not appear until 40,000 years
ago
• tools, burials, living sites, and occasional hints
of art and social organization
• "Everybody would accept that by 40,000 years
ago, LANGUAGE is everywhere" (Stanford
University archaeologist Richard Klein)
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Delayed takeoff. The anatomy needed for speech
was in place before 150,000 years ago, but the signs
of complex language don't proliferate until around
40,000 years ago
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• Where/When was the first Language?
• What does comparative linguistics tell
us?
• What does an analysis of human
mitochondrial DNA tell us?
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The term Proto-World language
• the hypothetical latest common ancestor
of all the world's languages
• an ancient language
• all modern languages
• and language families
• Including all known dead languages
• would have been spoken roughly 200,000
years ago
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The Origin of Language
• Merritt Ruhlen:
• Suggests that if you go systematically
back and compare cognates
• you can eventually find a common
relationship among all languages
• Says that mitochondrial DNA analysis
suggests that it is true
• Critics suggest:
• that it is too easy to mistake words that
are not cognatic as cognates
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Proto-World language
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Chinese
Quechua
French
Greek
Dutch
Turkish
shui
sut'u
suée
hudor
schuit
su
'water'
'wet'
'sweat'
'water'
'boat'
'water'
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Proto-World language
• Chinese
Quechua
Dutch
Greek
Latin
French
German
nü
ñusta
nuf
(gy)ne
(femi)na
nana
-in
'woman'
'princess'
'aloof girl'
'woman'
'woman'
'woman'
fem. suffix
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Blood factor Rhesus negative
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Are there any answers in
language acquisition theory?
Critical Age hypothesis:
• Order of language development
• Babbling
• One-word stage
• Two-word stage
• Telegraphic speech
• Orderly addition of grammar
• Orderly addition of cognitive concepts
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A new stage in human evolution
• The origin of language
• the beginning of culture, including art, desire,
and the sacred
• new forms of social organization which are
radically different from animal
• language is so radically different from animal
communication systems
• its origin must have been a singular event
• Since this event leaves no fossil record
• only hypothesize about the conditions of its
origin
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• For archaeologists eager to learn
how we became human
• when and how LANGUAGE
emerged is a crucial question
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“Speech” is a wonderful
gift from God
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