Miyerkules, Marso 20, 2013

Nonlinguistic Influences

Nonlinguistic factors can be involved in and sometimes interfere with linguistic processing.

1. Two compound nouns both start with the same sound, are composed of two syllable, have the same stress pattern, and contain the identical second morphemes undoubtedly played a role in producing the error.
examples: He made hairlines. - He made headlines.

2.  Similar comments apply to the congressional representatives.
examples: It can deliver a large payroll. - It can deliver a large payload.

3. Thoughts unrelated in form to the intended utterance may have an influence on what is said. The two phrases are not similar phonologically or morphologically, yet the nonlinguistic association seems to have influenced what was said.
examples: I've never heard of classes on April 9. - I've never heard of classes on Good Friday.

Computer Processing of Human Language

Computational Linguistics - subfield of linguistics and computer science that is concerned with the interactions of human language and computers.
It involves the ff:
a. analysis of written texts and spoken discourse
b. translation of text and speech from one language into another
c. use of human languages for communication between computers and people
d. modeling and testing of linguistic theories

Computers that talk and Listen

Computational phonetics and phonology - concerned with processing sounds. Goals: conveting speech to text on the comprehension side and text to speech on the production side.
Computational morphology, computational syntax, computational semantics, computational pragmatics - concerned with higher levels of linguistic processing.

Computational Phonetics and Phonology

Two sides of computational phonetics and phonology:
a. speech recognition - process of analyzing the speech signal into its component phones and phonemes, and producing, in effect, a phonetic transcription of the speech.

b. speech synthesis - process of creating electronic signals that stimulate the phones and prosodic features of speech and assemble them into words and phrases for output to an electronic speaker, or for further processing as in a speech generation application.

Computational Morphology

Computational Morphology - processing of word structures by computers.
Stemming - affixes are detected and repeatedly stripped of the beginning and end of words, checking the work against computer's dictionary.

Computational Syntax

Parser - a computer program that attempts to replicate what we have been calling the "mental parser".
a. Top-down parser - proceeds by first consulting the grammar rules and then examining the input string to see if the first word could begin an S.
b. Bottom-up parser - it looks first at the input string and finds a Det (the) followed by an N (child).

Computational Semantics

Computational Semantics - to produce a semantic representation in the computer of language input; the other is to take a semantic representation and produce natural language output that conveys the meaning.
Speech understanding - computer tries to find concepts in its semantic representation capabilities that fit the words and structures of the input.
Computational Pragmatics

Reference resolution - to determine when two expressions refer to the same object.








Biyernes, Marso 15, 2013

Brain and Language



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Neurolinguistics – the study of the biological and neural
foundations of language.
- the study of the brain mechanisms and anatomical structures that underlie linguistic competence and performance.
Brain – consists of approximately 100 billion nerve cells
            - composed of cerebral hemispheres; one from the right
and left; joined the corpus callosum (network of more than
200 million fibers).
- most complex organ of the body, controlling motor and sensory activities and thought processes.
Cortex – surface of the brain; gray matter; decision making
organ of the body; receives the memories from all sensory
organs; initiates all voluntary and involuntary actions;
storehouse of memories.
Contralateral functions – the left hemisphere controls the right
side of the body and the tight hemisphere
controls the left side.
Localization – proposed by Franz Joseph Gall
-         different human cognitive abilities and behaviors are localized in specific parts of the brain.
-         Language is located at the frontal lobes of the brain and the most articulate and intelligent of his fellow students had protruding eyes.
Phrenology – organology; practice of determining personality
traits, intellectual capacities and other matters by examining the bumps on the skull.
Johann Spurzheim- Gall’s disciple introduced phrenology to America.
Aphasia – neurological term for any language disorder that
results from brain damaged caused by a disease or trauma.
Broca’s Area – French surgeon Paul Broca
-         language is localized to the left hemisphere of the brain. And more specifically to the front part of the left hemisphere.
Wernicke’s area – Carl Wernicke, a german neurologist
- described another vriety of aphasia that occurred in patients with lesions in areas of the left hemisphere temporal lobe.
Lateralization – localization of function to one hemisphere of
the brain.
Broca’s Aphasia – characterized by labored speech and certain
kinds of word finding difficulties, but it is primarily a disorder that affects a person’s ability to form sentences with the rules of syntax.
-         agramatic (it frequently lacks articles, prepositions, pronouns, auxiliary verbs, and other grammatical elements or function words)
-         have difficulty understanding complex sentences
-         impaired syntax and agrammatism
Wernicke’s Aphasia – produce fluent speech with good
intonation, and they may largely adhere to the rules of syntax; make numerous lexical errors and often producing jargon and nonsense words.
Jargon Aphasia – severe Wernicke’s Aphasia
                        - Speakers produce nonsense forms that make their
utterance uninterpretable.
Anomia – a form of aphasia in which the patint has word-finding
difficulties.
Dyslexia – reading disorder
Acquired dyslexics – before their brain lesions they were normal
readers

Developmental dyslexics- difficulty learning to read.
Japanese language – kana (sound system; each symbol
corresponds to a syllable) and kanji (ideographic; each symbol corresponds to a word)
Tip-of-the-tongue phenomenon (TOT) – severe anomia;
inability to find the word you wish to speak.
* Language difficulties suffered by aphasics are not caused by any general cognitive or intellectual impairment or loss of motor or sensory controls of the nerves and muscles of the speech organs or hearing apparatus. Aphasics can produce and hear sounds. Whatever loss they suffer has to do only with the language faculty (or specific parts of it).
Left hemisphere – lateralized for language; abstract system for
symbols and rules
Pliny the Elder – refers to an Athenian who “with a stroke a
stone fell presently to forget his letters only, and
could read no more; otherwise, his memory served
him well enough.”
Carl Linneus – published a case study of a man suffering from jargon aphasia.
Noninvasive brain recording technologies:
·        Computer tomography scan (CT Scan) and Magnetic Resonance Imaging (MRI) – can reveal lesions in the living brain shortly after the damage occurs
·        Positron Emission Tomography (PET) scans, Functional MRI scans and Single Photon Emission CT (SPECT) scans – provide images of the brain in action.
Magnetic Encephalography (MEG) – measures magnetic fields
in the living brain.
* Wernicke’s area is visibly distinctive in the left hemisphere of the fetus by the twenty-sixth gestational week. Infants as young as one week old show a greater electrical response in the left hemisphere to language and in the right hemisphere to music.
Brain’s Plasticity (flexibility)- the right hemisphere can take over many of the language functions that would normally reside in the left hemisphere.
Hemispherectomy – one hemisphere of the brain is surgically
removed; the procedure is used to treat
intractable case of epilepsy.
* Human brain is essentially designed to specialized for language in the left hemisphere but that the right hemisphere is involved in early language development.
* When the brain is surgically split, certain information from the left side of the body is received only by the right side o the brain and vice versa.
* In humans who have undergone split-brain operations, the two hemispheres appear to be independent, and messages sent to the brain result in different responses, depending on which side receives the message.
* The left hemisphere is superior for language, rhythmic perception, temporal-order judgments, and arithmetic calculations.
* Studies of human spli-brain patients have also shown that when the interhemispheric visual connections are severed, visual information from the right and the left visual becomes confined to the left and right hemispheres, respectively.
Dichotic listening- an experimental technique that uses auditory
signals to observe the behavior of the
individual hemispheres of the human brain.
Ipsilateral – same side
* The left hemisphere is not superior for processing all sounds, it is only better for those sounds that are linguistic.
Event-related brain potentials (ERP) – electrical signals
emitted from the brain in response to different
stimuli.
                                                            - the left hemisphere is
sensitive to grammatical structure even in the
absence of meaning.
Jabberwocky sentences – sentences that are grammatical but
contain nonsense words.
Specific Language Impairment (SLI) – only their linguistic
ability is affected, and not often only specific aspects of grammar are impaired.
                                                - children have problems with the use
of function words such as articles,
prepositions, and auxiliary
verbs, have difficulties with
inflectional suffixes on
nouns and verbs such as markers of
tense and agreement.
Savants – intellectually handicapped individuals who, despite
their disabilities in certain spheres, show
remarkable talents in others.
Turner Syndrome – have normal language and advanced
reading skills along with serious
nonlinguistic (visual and spatial) cognitive
deficits.
Williams syndrome – reveal a unique behavioral profile in
which certain linguistic functions seem to be relatively preserved in the face of visual and spatial cognitive deficits and moderate retardation.
Developmental dyslexia and SLI – have a genetic basis.
Klinefelter syndrome – show quite selective syntactic and
semantic deficits alongside intact
intelligence.
*Monozygotic (identical) twins are more likely to both suffer from SLI than dizygotic (fraternal) twins.
Critical-age hypothesis – assumes that language is biologically
based and that the ability to learn a
native language develops within a
fixed period, from birth to middle
childhood.
                                    - there is a window of opportunity between
birth and middle childhood for learning a
first language.
*Language acquisition, though an innate, neurologically based ability, must be triggered by input from the environment.
*The cases of Genie and other isolated children, as well as deaf late learners of ASL, show that children cannot fully acquire language unless they are exposed to it within the critical period – a biologically determined window of opportunity during which time the brain is prepared to develop language.
*The languages of our human ancestors of millions of years ago may have been syntactically and phonologically simpler than any language known to us today.
*The language faculty is modular (independent of other cognitive systems with which it interacts). Can be found in aphasia, SLI, savants and who learn past the critical period.