phonology (sounds), morphology (words), syntax (sentence structure), semantics (meaning), and
pragmatics (use). Linguists try to find systematic descriptions capturing the regularities inherent in the
language itself. But a description of natural language just as a abstract structured system, can not be
enough. Psycholinguists rather ask, how the knowledge of language is represented in the brain, and
how it is used. Todays most important research topics are:
1. comprehension: How humans understand spoken as well as written language, how
language is processed and what interactions with memory are involved.
2. speech production: Both the physical aspect of speech production, and the mental process
that stands behind the uttering of a sentence.
3. acquisition: How people learn to speak and understand a language.
Characteristic features
What is a language? What kinds of languages do exist? Are there characteristic features that are
unique in human language?
There are plenty of approaches how to describe languages. Especially in computational linguistics
researchers try to find formal definitions for different kinds of languages. But for psychology other
aspects are of central interest. Language is also a tool we use for social interactions starting with the
exchange of news up to the identification of social groups by their dialect. We use it for expressing our
feelings, thoughts, ideas etc. But aboveall it is a system of communication.
Although there are plenty ways to communicate (see Non-Human-Language) humans expect their
system of communication - the human language to be unique. But what is it that makes the human
language so special and unique?
Four major criteria were proposed by Professor Schmalhofer from the University of Osnabrück.
The first criterion he names is semanticity which means the usage of symbols. Symbols can either
refer to objects or to relations between objects. In the human language words are the basic form of
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symbols. For example the word "book" refers to an object made of paper on which something might be
written. A relation symbol is the verb "to like" which refers to the sympathy of somebody to something
or someone. Not only objects or relations at presence can be described but there are also symbols which
refer to objects in another time or place which is the criterion of displacement. The word "yesterday"
refers to day before and objects mentioned in a sentence with "yesterday" refer to objects from another
time than the present one. Displacement is about the communication of events which had happened or
will happen and the objects belonging to that event.
Having a range of symbols to communicate these symbols can be newly combined. Creativity is
the probable most important feature. Our communication is not restricted to a fixed set of topics or
predetermined messages. The combination of a finite set of symbols to an infinite number of sentences
and meaning. With the infinite number of sentences the creation of novel messages is possible. How
creative the human language is can be illustrated by some simple examples like the process that creates
verbs from nouns. New words can be created, which do not exist so far, but we are able to understand
them:
leave the boat on the beach -> beach the boat
keep the aeroplane on the ground -> ground the aeroplane
write somebody an e-mail -> e-mail somebody
Creative systems are also found in other aspects of language, like the way sounds are combined to
form new words. i.e. prab, orgu, zabi could be imagined as names for new products. To avoid an
arbitrary combination of symbols without any regular arrangement "true" languages need structure
dependency. Combining symbols the syntax is relevant. A change in the symbol order might have an
impact on the meaning of the sentence.
Non-Human Language - Animal Communication
To dicuss the issues of language we first have to know what language is about and what it is that
makes the human communication system so unique and different to other communication system.
Human language is just one of quite a number of communication forms. Different forms of
communication can be found in the world of animals. From a little moth to a giant whale, all animals
appear to have the use of communication.
Forms of Communication
First of all there is the non-vocal communication. A well known non-verbal communication
method is the facial expression. Not only humans use facial expression for stressing utterances or
feeling, facial expressions can be found among apes. The expression, for example "smiling" indicates
cooperativeness and friendliness in both the human and the ape world. On the other hand an ape
showing teeth indicates the willingness to fight.
Another way of communication is the gesture as an active posturing. Humans shake hands as a
greeting or agreement after a bargain. Dogs wave their tail when they are excited and cats start purring
when they feel relaxed. Besides gestures sometimes involve the whole body and its pose. That is called
posture. Posture is a very common communicative tool among animals. Lowering the front part of the
body and extending the front legs is a sign of dogs that they are playful whereas lowering the full body
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is a dog’s postural way to show its submissiveness. Postural communication is known in both human
and non-human primates.
However there are other not that obvious ways to communicate. Facial expression, gesture and
posture are found in human communication. Furthermore there are other communicative devices which
are either just noticeable by the sub-consciousness of humans like scent or cannot be found amongst
humans like light, colour and electricity. Scent is a chemically based type of communication. The
chemicals which are used for a communicative function are called pheremones. Those pheremones are
used to mark territorial or to signal its reproductive readiness. For animals scent is a very important tool
which predominates their mating behaviour. Humans are influenced in their mating behaviour by scent
as well but there are more factors to that behaviour so that scent is not predominating.
Light is a communicative device mainly used by insects like the firefly and the lightning bug
which can be found in North America. The insects use species-dependent light patterns to signal
identity, sex and location. Another device which cannot be found in human communication but just
among some eels in the Amazon River is electricity. With the help of electrical impulses at various
frequencies those eels are able to communicate about their territory and their presence. Furthermore
colour plays an important role among animals to identify members of their species and other animals.
For example the octopus changes colour for signalling territorial defence and mating readiness. In the
world of birds colour is wide spread, too. The male peacock has colourful feathering to impress female
peahens as a part of mating behaviour. These ways of communication help to live in a community and
survive in nature.
Characteristic Language Features in Animal Communication
As mentioned above there are four criteria (semanticity, displacement, creativity and structural
dependency) which are important devices in the human language to form a clear communication
between humans. To see if these criteria exist in animal communication - i.e. if animals possess a "true"
language - several experiments with non-human primates were performed. Non-human primates were
taught American Sign Language (ASL) and a specially developed token language to detect in how far
they are capable of linguistic behaviour. Can semanticity, displacement, creativity and structure
dependence be found in non-human language?
Experiments
Viki
In 1948 two psychologists tried to teach English words to a chimpanzee named Viki. The
chimpanzee was wanted to speak easy English words like "cup". The experiment failed since with the
supralanyngal anatomy and the vocal fold structure that chimpanzees have it is impossible for them to
produce human speech sounds. The failure of the Viki experiment made scientists wonder how far are
non-human primates able to communicate linguistically.
Washoe
From 1965 to 1972 the first important evidence showing rudiments of linguistic behaviour was
"Washoe", a young female chimpanzee. The experimenters Allen and Beatrice Gardner conducted an
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experiment where Washoe learned 130 signs of the American Sign Language within three years.
Showing pictures of a duck to Washoe and asking WHAT THAT? she combined the symbols of
WATER and BIRD to create WATER BIRD as she had not learned the word DUCK (the words in
capital letters refer to the signs the apes use to communicate with the experimenter).
It was claimed that Washoe was able to arbitrarily combine signs spontaneously and creatively.
Some scientists criticised the ASL experiment of Washoe because they claimed that ASL is a loose
communicative system and strict syntactic rules are not required. Because of this criticism different
experiments were developed and performed which focus on syntactic rules and structure dependency as
well as on creative symbol combination.
Sarah
A young female chimp called "Sarah" was trained by Premack in 1972. Sarah learned 100 symbols
and she was asked to produce simple sentences like MARY GIVE BANANA SARAH. The production
of a correctly structured sentences were rewarded. She also was able to deal with more abstract words
like IF/THEN.
Kanzi
Another non-human primate named "Kanzi" was trained by Savage-Rumbaugh in 1990. Kanzi was
able to deal with 256 geometric symbols and understood complex instructions like GET THE
ORANGE THAT IS IN THE COLONY ROOM. Again the experimenter worked with rewards. A
question which arose was whether these non-human primates were able to deal with human-like
linguistic capacities or if they were just trained to perform a certain action to get the rewarded.
Can the characteristic language features be found in non-human communication?
Creativity seems to be present in animal communication as amongst others Washoe showed with
the creation of WATER BIRD for DUCK. Although some critics claimed that creativity is often
accidental or like in the case of Washoe’s WATER BIRD the creation relays on the fact that water and
bird were present. Just because of this presence Washoe invented the word WATER BIRD. In the case
of Kanzi a certain form of syntactic rules was observed. In 90% of Kanzi’s sentences there was first the
invitation to play and then the type of game which Kanzi wanted to play like CHASE HIDE, TICKLE
SLAP and GRAB SLAP. The problem which was observed was that it is not always easy to recognise
the order of signs. Often facial expression and hand signs are performed at the same time. One ape
signed the sentence I LIKE COKE by hugging itself for “like” and forming the sign for “coke” with its
hands at the same time. Noticing an order in this sign sentence was not possible.
A certain structural dependency could be observed at Kanzi’s active and passive sentences. When
Matata, a fellow chimpanzee was grabbed Kanzi signed GRAB MATATA and when Matata was
performing an action such as biting Kanzi produced MATATA BITE. It has not yet been proved that
symbolic behaviour is occurring. Although there are plenty evidences that creativity and displacement
occur in animal communication some critics claim that these evidences can be led back to dressage and
training. It was claimed that linguistic behaviour cannot be proved as it is more likely to be a training to
correctly use linguistic devices. Apes show just to a little degree syntactic behaviour and they are not
able to produce sentences containing embedded structures. Some linguists claim that because of such a
lack of linguistic features non-human communication cannot be a “true” language. Although we do not
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know the capacity of an ape's mind it does not seem that the range of meanings observed in ape's wild
life approach the capaciousness of semanticity of human communication. Furthermore apes seem not to
care to much about displacement as it appears that they do not communicate about imaginary pasts or
futures.
All in all non-human primate communication consisting of graded series of communication shows
little arbitrariness. The results with non-human primates led to a controversial discussion about
linguistic behaviour. Many researchers claimed that the results were influenced by dressage. However
human lack certain communicative devices as well. Humans are not able to follow scent trails or
change their colour if they are in danger or in love. Humans are not even able to interpret posture and
subtle gesture as precise as a dog or a horse might interpret it.
Language is a communication form for humans suited to the patterns of human life. Other
communication systems are better suited for fellow creatures and their mode of existence.
Now that we know what we know that there is a difference between animal communication and
human language we will see detailed features of the human language.
Language Comprehension & Production
Language features – Syntax and Semantics
In this chapter the main question will be “how do we understand sentences?”. To find an answer to
that problem it is necessary to have a closer look at the structure of languages. The most important
properties every human language provides are rules which determine the permissible sentences and a
hierarchical structure (phonemes as basic sounds, which constitute words, which in turn costitute
phrases, which consitute sentences, which consitute stories). These feature of a language enable
humans to create new unique sentences. Due to this fact that all human languages have a common
ground even if they developed completely independent from one another the very interesting
conclusion can be drawn that the ability to speak a language must be innate. Another evidence of a
inborn universal grammar is that there were observations of deaf children who were not taught a
language and developed there own form of communication which provided the same basic constituents.
Two basic abilities human beings have to communicate is to interpret the syntax of a sentence and the
knowledge of the meaning of single words, which in combination enables them to understand the
semantic of whole sentences. Many experiments have been done to find out how the syntactical and
semantical interpretation is done by human beings and how syntax and semantics works together to
construct the right meaning of a sentence. Physiological experiments had been done in which for
example the event-related potential (ERP) in the brain was measured as well as behavioristic
experiments in which mental chronometry, the measurement of the time-course of cognitive processes,
was used. Physiological experiments showed that the syntactical and the semantical interpretation of a
sentence takes place separately from each other.
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Physiological Approach
Semantics
The exploration of the semantic sentence processing can be done by the measurement of the event-
related potential (ERP) when hearing a semantical correct sentence in comparison to a semantical
incorrect sentence. For example there was done an experiment in which three reactions to sentences
were compared:
Semantically correct: “The pizza was too hot to eat.”
Semantically wrong: “The pizza was too hot to drink.”
Semantically wrong: “The pizza was too hot to cry.”
In such experiments the ERP evoked by the correct sentence is considered to show the ordinary
sentence processing. The variations in the ERP in case of the incorrect sentences in contrast to the ERP
of the correct sentence show at what time the mistake is recognized. In case of semantic incorrectness
there was observed a strong negative signal about 400ms after perceiving the critical word which did
not occure if the sentence was semantically correct. These effects were observed mainly in the paritial
and central area. There was also found evidence that the N400 is the stronger the less the word fits
semantically. The word “drink” which fits a little bit more in the context caused a weaker N400 than
the word “cry”. That means the intensity of the N400 correlates with the degree of difficulty of the
semantic mistake. The more difficult it is to search for a semantic interpretation of a sentence the
higher is the N400 response.
Syntax
To examine the syntactical aspects of the sentence processing a quite similar experiment as in the
case of the semantic processing was done. There were used syntactical correct sentences and incorrect
sentences, such as (correct:)“The cats won´t eat…” and (incorrect:)“The cats won´t eating…”. When
perceiving an syntactical incorrect sentence in contrast to an syntactical correct sentence the ERP
changes significantly on two different points of time. First of all there a very early increased response
to syntactical incorrectness after 120ms. This signal is called the ‘early left anterior negativity’ because
it occurs mainly in the left frontal lobe. This advises that the syntactical processing is located amongst
others in the Broca-area which is located in the left frontal lobe. The early response to syntactical
mistakes also gives a hint that the syntactical mistakes are detected earlier than semantic mistakes.
The other change in the ERP when perceiving a syntactical wrong sentence occurs after 600ms in
the paritial lobe. The signal is increasing positively and is therefore called P600. Possibly the late
positive signal is reflecting the attempt to reconstruct the grammatical problematic sentence to find a
possible interpretation.
Summing up… There are three important ERP-components. First of all there occurs the ELAN at
the left frontal lobe which shows a violation of syntactical rules. After it follows the N400 in central
and paritial areas as a reaction to a semantical incorrectness and finally there takes place a P600 in the
paritial area which probably means a reanalysis of the wrong sentence.
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Behavioristic Approach – Parsing a Sentence
Behavioristic experiments about how human beings parse a sentence often use syntactically
ambiguous sentences. Because it is easier to realize that sentence-analysing mechanism called parser
takes place when using sentences in which we cannot automatically constitute the meaning of the
sentence. There are two different theories about how humans parse sentences. One of these theories
clames that syntax plays the main part whereas semanitcs has only a supporting role, the syntax-first
approach, the other theory states that both syntax and semantics work together to determine the
meaning of a sentence, the interactionist approach.
The Syntax-First Approach of Parsing
The syntax-first approach concentrates on the role of syntax when parsing a sentence. That humans
infer the meaning of a sentence with help of its syntactical structure (Kako and Wagner 2001) can
easily be seen when considering Lewis Carrollś poem ‘Jabberwocky’:
"Twas brillig, and the slithy toves Did gyre and gimble in the wabe: All mimsy were the
borogoves, And the mome raths outgrabe."
Although most of the words in the poems have no meaning one is able to understand the poem
somehow because of its syntactical structure.
There are many different syntactic rules that are used when parsing a sentence. One important rule
is the principle of late closure which means that a person assumes that a new word he perceives is part
of the current phrase. That this principle is used for parsing sentences can be seen very good with help
of a so called garden-path sentence. Experiments with garden-path sentences have been done by Frazier
and Fayner 1982. One example of a garden-path sentence is: “Because he always jogs a mile seems a
short distance to him.” When reading this sentence one first wants to continue the phrase “Because he
always jogs” by adding “a mile” to the phrase, but when reading further one realizes that the words “a
mile” are the beginning of a new phrase. This shows that we parse a sentence by trying to add new
words to a phrase as long as possible. Garden-path sentences show that we use the principle of late
closure as long it makes syntactically sense to add a word to the current phrase but when the sentence
starts to get incorrect semantics are often used to rearrange the sentence. The syntax-first approach does
not disregard semantics. According to this approach we use syntax first to parse a sentence and
semantics is later on used to make sense of the sentence.
There have not only been done experiments which show how syntax is used for parsing sentences
but also how semantics can influence the sentence processing. One important experiment about that
issue has been done by Daniel Slobin in 1966. He showed that passive sentences are understood faster
if the semantics of the words allow only one subject to be the actor. Sentences like “The horse was
kicked by the cow.” and “The fence was kicked by the cow.” are grammatically equal and in both cases
only one syntactical parsing is possible. Nevertheless the first sentence semantically provides two
subjects as possible actors and therefore it needs longer to parse this sentence. By measuring this
significant difference Daniel Slobin showed that semantics play an important role in parsing a sentence,
too.
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The Interactionist Approch of Parsing
The interactionist approach ascribes a more central role to semantics in parsing a sentence. In
contrast to the syntax-first approach, the interactionist theory clames that syntax is not used first but
that semantics and syntax are used simultanuasly to parse the sentence and that they work together in
clearifying the meaning. There have been made several experiments which provide evidence that
semantics are taking into account from the very beginning reading a sentence. Most of these
experiments are working with the eye-tracking techniques and compare the time needed to read
syntactical equal senences in which critical words cause or prohibit ambiguitiy by semantics. One of
these experiments has been done by John Trueswell and coworkers in 1994. He measured the eye
movement of persons when reading the following two sentences:
The defendant examined by the lawyer turned out to be unreliable. The evidence examined by the
lawyer turned out to be unreliable.
He observed that the time needed to read the words “by the lawyer” took longer in case of the first
sentence because in the first sentence the semanics first allow an interpretation in which the defendant
is the one who examines, while the evidence only can be examined. This experiment shows that the
semantics also play a role while reading the sentence which supports the interactionist approach and
argues against the theory that semantics are only used after a sentence has been parsed syntactically.
Situation Model
A situation model is a mental representation of what a text is about. This approach proposes t