Computational linguistics is an
interdisciplinary
Interdisciplinarity or interdisciplinary studies involves the combination of multiple academic disciplines into one activity (e.g., a research project). It draws knowledge from several other fields like sociology, anthropology, psychology, ec ...
field concerned with the
computational modelling
Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be deter ...
of
natural language
In neuropsychology, linguistics, and philosophy of language, a natural language or ordinary language is any language that has evolved naturally in humans through use and repetition without conscious planning or premeditation. Natural languag ...
, as well as the study of appropriate computational approaches to linguistic questions. In general, computational linguistics draws upon
linguistics
Linguistics is the scientific study of human language. It is called a scientific study because it entails a comprehensive, systematic, objective, and precise analysis of all aspects of language, particularly its nature and structure. Lingu ...
,
computer science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includin ...
,
artificial intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machine
A machine is a physical system using Power (physics), power to apply Force, forces and control Motion, moveme ...
,
mathematics,
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premis ...
,
philosophy,
cognitive science,
cognitive psychology
Cognitive psychology is the scientific study of mental processes such as attention, language use, memory, perception, problem solving, creativity, and reasoning.
Cognitive psychology originated in the 1960s in a break from behaviorism, which ...
,
psycholinguistics
Psycholinguistics or psychology of language is the study of the interrelation between linguistic factors and psychological aspects. The discipline is mainly concerned with the mechanisms by which language is processed and represented in the mind ...
,
anthropology
Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, societies, and linguistics, in both the present and past, including past human species. Social anthropology studies patterns of be ...
and
neuroscience
Neuroscience is the science, scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a Multidisciplinary approach, multidisciplinary science that combines physiology, an ...
, among others.
Sub-fields and related areas
Traditionally, computational linguistics emerged as an area of
artificial intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machine
A machine is a physical system using Power (physics), power to apply Force, forces and control Motion, moveme ...
performed by
computer scientist
A computer scientist is a person who is trained in the academic study of computer science.
Computer scientists typically work on the theoretical side of computation, as opposed to the hardware side on which computer engineers mainly focus ( ...
s who had specialized in the application of computers to the processing of a
natural language
In neuropsychology, linguistics, and philosophy of language, a natural language or ordinary language is any language that has evolved naturally in humans through use and repetition without conscious planning or premeditation. Natural languag ...
. With the formation of the
Association for Computational Linguistics (ACL) and the establishment of independent conference series, the field consolidated during the 1970s and 1980s.
The Association for Computational Linguistics defines computational linguistics as:
The term "computational linguistics" is nowadays (2020) taken to be a near-synonym of
natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
(NLP) and
language technology. These terms put a stronger emphasis on aspects of practical applications rather than theoretical inquiry. In practice, they have largely replaced the term "computational linguistics" in the NLP/ACL community, although they specifically refer to the sub-field of applied computational linguistics, only.
Computational linguistics has both theoretical and applied components. Theoretical computational linguistics focuses on issues in
theoretical linguistics
Theoretical linguistics is a term in linguistics which, like the related term general linguistics, can be understood in different ways. Both can be taken as a reference to theory of language, or the branch of linguistics which inquires into the ...
and cognitive science.
[ Applied computational linguistics focuses on the practical outcome of modeling human language use.]
Theoretical computational linguistics includes the development of formal theories of grammar
In linguistics, the grammar of a natural language is its set of structure, structural constraints on speakers' or writers' composition of clause (linguistics), clauses, phrases, and words. The term can also refer to the study of such constraint ...
(parsing
Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from Lati ...
) and semantics
Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference, meaning, or truth. The term can be used to refer to subfields of several distinct disciplines, including philosophy, linguistics and compu ...
, often grounded in formal logics and symbolic
Symbolic may refer to:
* Symbol, something that represents an idea, a process, or a physical entity
Mathematics, logic, and computing
* Symbolic computation, a scientific area concerned with computing with mathematical formulas
* Symbolic dynamic ...
(knowledge-based
The knowledge economy (or the knowledge-based economy) is an economic system in which the production of goods and services is based principally on knowledge-intensive activities that contribute to advancement in technical and scientific inn ...
) approaches. Areas of research that are studied by theoretical computational linguistics include:
*Computational complexity
In computer science, the computational complexity or simply complexity of an algorithm is the amount of resources required to run it. Particular focus is given to computation time (generally measured by the number of needed elementary operations) ...
of natural language, largely modeled on automata theory
Automata theory is the study of abstract machines and automata, as well as the computational problems that can be solved using them. It is a theory in theoretical computer science. The word ''automata'' comes from the Greek word αὐτόματο� ...
, with the application of context-sensitive grammar
A context-sensitive grammar (CSG) is a formal grammar in which the left-hand sides and right-hand sides of any production rules may be surrounded by a context of terminal and nonterminal symbols. Context-sensitive grammars are more general than ...
and linearly bounded Turing machine
A Turing machine is a mathematical model of computation describing an abstract machine that manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, it is capable of implementing any computer algor ...
s.
* Computational semantics comprises defining suitable logics for linguistic meaning representation, automatically constructing them and reasoning with them
Applied computational linguistics has been dominated by statistical methods
Statistics (from German: '' Statistik'', "description of a state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industr ...
, like neural network
A neural network is a network or neural circuit, circuit of biological neurons, or, in a modern sense, an artificial neural network, composed of artificial neurons or nodes. Thus, a neural network is either a biological neural network, made up ...
s and machine learning
Machine learning (ML) is a field of inquiry devoted to understanding and building methods that 'learn', that is, methods that leverage data to improve performance on some set of tasks. It is seen as a part of artificial intelligence.
Machine ...
, since about 1990. Socher et al. (2012) was an early deep learning tutorial at the ACL 2012, and met with both interest and (at the time) scepticism by most participants. Until then, neural learning was basically rejected because of its lack of statistical interpretability. Until 2015, deep learning had evolved into the major framework of NLP. As for the tasks addressed by applied computational linguistics, see Natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
article. This includes classical problems such as the design of POS-taggers (part-of-speech taggers), parser
Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from Lati ...
s for natural language
In neuropsychology, linguistics, and philosophy of language, a natural language or ordinary language is any language that has evolved naturally in humans through use and repetition without conscious planning or premeditation. Natural languag ...
s, or tasks such as machine translation
Machine translation, sometimes referred to by the abbreviation MT (not to be confused with computer-aided translation, machine-aided human translation or interactive translation), is a sub-field of computational linguistics that investigates t ...
(MT), the sub-division of computational linguistics dealing with having computers translate between languages. As one of the earliest and most difficult applications of computational linguistics, MT draws on many subfields and both theoretical and applied aspects. Traditionally, automatic language translation has been considered a notoriously hard branch of computational linguistics.
Aside from dichotomy between theoretical and applied computational linguistics, other divisions of computational into major areas according to different criteria exist, including:
* medium of the language being processed, whether spoken or textual: speech recognition
Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the ma ...
and speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal languag ...
deal with how spoken language can be understood or created using computers.
* task being performed, e.g., whether analyzing language (recognition) or synthesizing language (generation): Parsing and generation are sub-divisions of computational linguistics dealing respectively with taking language apart and putting it together.
Traditionally, applications of computers to address research problems in other branches of linguistics have been described as tasks within computational linguistics. Among other aspects, this includes
* Computer-aided corpus linguistics
Corpus linguistics is the study of a language as that language is expressed in its text corpus (plural ''corpora''), its body of "real world" text. Corpus linguistics proposes that a reliable analysis of a language is more feasible with corpora ...
, which has been used since the 1970s as a way to make detailed advances in the field of discourse analysis
* Simulation and study of language evolution in historical linguistics
Historical linguistics, also termed diachronic linguistics, is the scientific study of language change over time. Principal concerns of historical linguistics include:
# to describe and account for observed changes in particular languages
# ...
/glottochronology Glottochronology (from Attic Greek γλῶττα ''tongue, language'' and χρόνος ''time'') is the part of lexicostatistics which involves comparative linguistics and deals with the chronological relationship between languages.Sheila Embleton ( ...
.[
]
Origins
Computational linguistics is often grouped within the field of artificial intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machine
A machine is a physical system using Power (physics), power to apply Force, forces and control Motion, moveme ...
but was present before the development of artificial intelligence. Computational linguistics originated with efforts in the United States in the 1950s to use computers to automatically translate texts from foreign languages, particularly Russian scientific journals, into English. Since computers can make arithmetic
Arithmetic () is an elementary part of mathematics that consists of the study of the properties of the traditional operations on numbers—addition, subtraction, multiplication, division, exponentiation, and extraction of roots. In the 19th c ...
(systematic) calculations much faster and more accurately than humans, it was thought to be only a short matter of time before they could also begin to process language. Computational and quantitative methods are also used historically in the attempted reconstruction of earlier forms of modern languages and sub-grouping modern languages into language families. Earlier methods, such as lexicostatistics
Lexicostatistics is a method of comparative linguistics that involves comparing the percentage of lexical cognates between languages to determine their relationship. Lexicostatistics is related to the comparative method but does not reconstruct a ...
and glottochronology Glottochronology (from Attic Greek γλῶττα ''tongue, language'' and χρόνος ''time'') is the part of lexicostatistics which involves comparative linguistics and deals with the chronological relationship between languages.Sheila Embleton ( ...
, have been proven to be premature and inaccurate. However, recent interdisciplinary studies that borrow concepts from biological studies, especially gene mapping
Gene mapping describes the methods used to identify the locus of a gene and the distances between genes. Gene mapping can also describe the distances between different sites within a gene.
The essence of all genome mapping is to place a c ...
, have proved to produce more sophisticated analytical tools and more reliable results.
When machine translation
Machine translation, sometimes referred to by the abbreviation MT (not to be confused with computer-aided translation, machine-aided human translation or interactive translation), is a sub-field of computational linguistics that investigates t ...
(also known as mechanical translation) failed to yield accurate translations right away, automated processing of human languages was recognized as far more complex than had originally been assumed. Computational linguistics was born as the name of the new field of study devoted to developing algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ...
s and software for intelligently processing language data. The term "computational linguistics" itself was first coined by David Hays, a founding member of both the Association for Computational Linguistics (ACL) and the International Committee on Computational Linguistics (ICCL).
To translate one language into another, it was observed that one had to understand the grammar
In linguistics, the grammar of a natural language is its set of structure, structural constraints on speakers' or writers' composition of clause (linguistics), clauses, phrases, and words. The term can also refer to the study of such constraint ...
of both languages, including both morphology (the grammar of word forms) and syntax (the grammar of sentence structure). To understand syntax, one had to also understand the semantics
Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference, meaning, or truth. The term can be used to refer to subfields of several distinct disciplines, including philosophy, linguistics and compu ...
and the lexicon (or 'vocabulary'), and even something of the pragmatics
In linguistics and related fields, pragmatics is the study of how context contributes to meaning. The field of study evaluates how human language is utilized in social interactions, as well as the relationship between the interpreter and the in ...
of language use. Thus, what started as an effort to translate between languages evolved into an entire discipline devoted to understanding how to represent and process natural languages using computers.
Nowadays research within the scope of computational linguistics is done at computational linguistics departments, computational linguistics laboratories, computer science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includin ...
departments, and linguistics departments.
Some research in the field of computational linguistics aims to create working speech or text processing systems while others aim to create a system allowing human-machine interaction. Programs meant for human-machine communication are called conversational agents
A dialogue system, or conversational agent (CA), is a computer system intended to converse with a human. Dialogue systems employed one or more of text, speech, graphics, haptics, gestures, and other modes for communication on both the input and o ...
.
Approaches
Just as computational linguistics can be performed by experts in a variety of fields and through a wide assortment of departments, so too can the research fields broach a diverse range of topics. The following sections discuss some of the literature available across the entire field broken into four main area of discourse: developmental linguistics, structural linguistics, linguistic production, and linguistic comprehension.
Developmental approaches
Language is a cognitive skill that develops throughout the life of an individual. This developmental process has been examined using several techniques, and a computational approach is one of them. Human language development
Language development in humans is a process starting early in life. Infants start without knowing a language, yet by 10 months, babies can distinguish speech sounds and engage in babbling. Some research has shown that the earliest learning begi ...
does provide some constraints which make it harder to apply a computational method to understanding it. For instance, during language acquisition
Language acquisition is the process by which humans acquire the capacity to perceive and comprehend language (in other words, gain the ability to be aware of language and to understand it), as well as to produce and use words and sentences to ...
, children are largely only exposed to positive evidence. This means that during the linguistic development of an individual, the only evidence for what is a correct form is provided, and no evidence for what is not correct. This is insufficient information for a simple hypothesis testing procedure for information as complex as language,[Braine, M.D.S. (1971). On two types of models of the internalization of grammars. In D.I. Slobin (Ed.), The ontogenesis of grammar: A theoretical perspective. New York: Academic Press.] and so provides certain boundaries for a computational approach to modeling language development and acquisition in an individual.
Attempts have been made to model the developmental process of language acquisition in children from a computational angle, leading to both statistical grammars and connectionist models.[Powers, D.M.W. & Turk, C.C.R. (1989). ''Machine Learning of Natural Language''. Springer-Verlag. .] Work in this realm has also been proposed as a method to explain the evolution of language through history. Using models, it has been shown that languages can be learned with a combination of simple input presented incrementally as the child develops better memory and longer attention span. This was simultaneously posed as a reason for the long developmental period of human children.[ Both conclusions were drawn because of the strength of the ]artificial neural network
Artificial neural networks (ANNs), usually simply called neural networks (NNs) or neural nets, are computing systems inspired by the biological neural networks that constitute animal brains.
An ANN is based on a collection of connected units ...
which the project created.
The ability of infants to develop language has also been modeled using robots in order to test linguistic theories. Enabled to learn as children might, a model was created based on an affordance
Affordance is what the environment offers the individual. American psychologist James J. Gibson coined the term in his 1966 book, ''The Senses Considered as Perceptual Systems'', and it occurs in many of his earlier essays. However, his best-kno ...
model in which mappings between actions, perceptions, and effects were created and linked to spoken words. Crucially, these robots were able to acquire functioning word-to-meaning mappings without needing grammatical structure, vastly simplifying the learning process and shedding light on information which furthers the current understanding of linguistic development. It is important to note that this information could only have been empirically tested using a computational approach.
As our understanding of the linguistic development of an individual within a lifetime is continually improved using neural networks and learning robotic systems, it is also important to keep in mind that languages themselves change and develop through time. Computational approaches to understanding this phenomenon have unearthed very interesting information. Using the Price equation and Pólya urn
Pólya (Hungarian for "swaddling clothes") is a surname. People with the surname include:
* Eugen Alexander Pólya (1876-1944), Hungarian surgeon, elder brother of George Pólya
** Reichel-Polya Operation, a type of partial gastrectomy developed ...
dynamics, researchers have created a system which not only predicts future linguistic evolution but also gives insight into the evolutionary history of modern-day languages. This modeling effort achieved, through computational linguistics, what would otherwise have been impossible.
It is clear that the understanding of linguistic development in humans as well as throughout evolutionary time has been fantastically improved because of advances in computational linguistics. The ability to model and modify systems at will affords science an ethical method of testing hypotheses that would otherwise be intractable.
Structural approaches
To create better computational models of language, an understanding of language's structure is crucial. To this end, the English language
English is a West Germanic language of the Indo-European language family, with its earliest forms spoken by the inhabitants of early medieval England. It is named after the Angles, one of the ancient Germanic peoples that migrated to t ...
has been meticulously studied using computational approaches to better understand how the language works on a structural level. One of the most important pieces of being able to study linguistic structure is the availability of large linguistic corpora or samples. This grants computational linguists the raw data necessary to run their models and gain a better understanding of the underlying structures present in the vast amount of data which is contained in any single language. One of the most cited English linguistic corpora is the Penn Treebank
In linguistics, a treebank is a parsed text corpus that annotates syntactic or semantic sentence structure. The construction of parsed corpora in the early 1990s revolutionized computational linguistics, which benefitted from large-scale empir ...
. Derived from widely-different sources, such as IBM computer manuals and transcribed telephone conversations, this corpus contains over 4.5 million words of American English. This corpus has been primarily annotated using part-of-speech
In grammar, a part of speech or part-of-speech ( abbreviated as POS or PoS, also known as word class or grammatical category) is a category of words (or, more generally, of lexical items) that have similar grammatical properties. Words that are a ...
tagging and syntactic bracketing and has yielded substantial empirical observations related to language structure.
Theoretical approaches to the structure of languages have also been developed. These works allow computational linguistics to have a framework within which to work out hypotheses that will further the understanding of the language in a myriad of ways. One of the original theoretical theses on the internalization of grammar
In linguistics, the grammar of a natural language is its set of structure, structural constraints on speakers' or writers' composition of clause (linguistics), clauses, phrases, and words. The term can also refer to the study of such constraint ...
and structure of language proposed two types of models.[ In these models, rules or patterns learned increase in strength with the frequency of their encounter.][ The work also created a question for computational linguists to answer: how does an infant learn a specific and non-normal grammar (]Chomsky normal form
In formal language theory, a context-free grammar, ''G'', is said to be in Chomsky normal form (first described by Noam Chomsky) if all of its production rules are of the form:
: ''A'' → ''BC'', or
: ''A'' → ''a'', or
: ''S'' → ...
) without learning an overgeneralized version and getting stuck?[ Theoretical efforts like these set the direction for research to go early in the lifetime of a field of study, and are crucial to the growth of the field.
Structural information about languages allows for the discovery and implementation of similarity recognition between pairs of text utterances.] For instance, it has recently been proven that based on the structural information present in patterns of human discourse, conceptual recurrence plots can be used to model and visualize trends in data and create reliable measures of similarity between natural textual utterances.[ This technique is a strong tool for further probing the structure of human ]discourse
Discourse is a generalization of the notion of a conversation to any form of communication. Discourse is a major topic in social theory, with work spanning fields such as sociology, anthropology, continental philosophy, and discourse analysis. ...
. Without the computational approach to this question, the vastly complex information present in discourse data would have remained inaccessible to scientists.
Information regarding the structural data of a language is available for English as well as other languages, such as Japanese. Using computational methods, Japanese sentence corpora were analyzed and a pattern of log-normality
In probability theory, a log-normal (or lognormal) distribution is a continuous probability distribution of a random variable whose logarithm is normally distributed. Thus, if the random variable is log-normally distributed, then has a norma ...
was found in relation to sentence length.[ Though the exact cause of this lognormality remains unknown, it is precisely this sort of information which computational linguistics is designed to uncover. This information could lead to further important discoveries regarding the underlying structure of Japanese and could have any number of effects on the understanding of Japanese as a language. Computational linguistics allows for very exciting additions to the scientific knowledge base to happen quickly and with very little room for doubt.
Without a computational approach to the structure of linguistic data, much of the information that is available now would still be hidden under the vastness of data within any single language. Computational linguistics allows scientists to parse huge amounts of data reliably and efficiently, creating the possibility for discoveries unlike any seen in most other approaches.
]
Production approaches
The production of language is equally as complex in the information it provides and the necessary skills which a fluent producer must have. That is to say, comprehension
Comprehension may refer to:
* Comprehension (logic), the totality of intensions, that is, properties or qualities, that an object possesses
* Comprehension approach, several methodologies of language learning that emphasize understanding languag ...
is only half the problem of communication. The other half is how a system produces language, and computational linguistics has made interesting discoveries in this area.
In a now famous paper published in 1950 Alan Turing
Alan Mathison Turing (; 23 June 1912 – 7 June 1954) was an English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. Turing was highly influential in the development of theoretical c ...
proposed the possibility that machines might one day have the ability to "think". As a thought experiment
A thought experiment is a hypothetical situation in which a hypothesis, theory, or principle is laid out for the purpose of thinking through its consequences.
History
The ancient Greek ''deiknymi'' (), or thought experiment, "was the most anci ...
for what might define the concept of thought in machines, he proposed an "imitation test" in which a human subject has two text-only conversations, one with a fellow human and another with a machine attempting to respond like a human. Turing proposes that if the subject cannot tell the difference between the human and the machine, it may be concluded that the machine is capable of thought. Today this test is known as the Turing test
The Turing test, originally called the imitation game by Alan Turing in 1950, is a test of a machine's ability to exhibit intelligent behaviour equivalent to, or indistinguishable from, that of a human. Turing proposed that a human evaluato ...
and it remains an influential idea in the area of artificial intelligence.
One of the earliest and best-known examples of a computer program designed to converse naturally with humans is the ELIZA
ELIZA is an early natural language processing computer program created from 1964 to 1966 at the MIT Artificial Intelligence Laboratory by Joseph Weizenbaum. Created to demonstrate the superficiality of communication between humans and machines ...
program developed by Joseph Weizenbaum
Joseph Weizenbaum (8 January 1923 – 5 March 2008) was a German American computer scientist and a professor at MIT. The Weizenbaum Award is named after him. He is considered one of the fathers of modern artificial intelligence.
Life and care ...
at MIT in 1966. The program emulated a Rogerian psychotherapist
Psychotherapy (also psychological therapy, talk therapy, or talking therapy) is the use of psychological methods, particularly when based on regular personal interaction, to help a person change behavior, increase happiness, and overcome prob ...
when responding to written statements and questions posed by a user. It appeared capable of understanding what was said to it and responding intelligently, but in truth, it simply followed a pattern matching routine that relied on only understanding a few keywords in each sentence. Its responses were generated by recombining the unknown parts of the sentence around properly translated versions of the known words. For example, in the phrase "It seems that you hate me" ELIZA understands "you" and "me" which matches the general pattern "you ome words
Ome may refer to:
Places
* Ome (Bora Bora), a public island in the lagoon of Bora Bora
* Ome, Lombardy, Italy, a town and ''comune'' in the Province of Brescia
* Ōme, Tokyo, a city in the Prefecture of Tokyo
* Ome (crater), a crater on Mars
Tran ...
me", allowing ELIZA to update the words "you" and "me" to "I" and "you" and replying "What makes you think I hate you?". In this example ELIZA has no understanding of the word "hate", but it is not required for a logical response in the context of this type of psychotherapy.
Some projects are still trying to solve the problem which first started computational linguistics off as its field in the first place. However, methods have become more refined, and consequently, the results generated by computational linguists have become more enlightening. To improve computer translation
Machine translation, sometimes referred to by the abbreviation MT (not to be confused with computer-aided translation, machine-aided human translation or interactive translation), is a sub-field of computational linguistics that investigates t ...
, several models have been compared, including hidden Markov models, smoothing techniques, and the specific refinements of those to apply them to verb translation. The model which was found to produce the most natural translations of German
German(s) may refer to:
* Germany (of or related to)
**Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ger ...
and French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
words was a refined alignment model with a first-order dependence and a fertility model. They also provide efficient training algorithms for the models presented, which can give other scientists the ability to improve further on their results. This type of work is specific to computational linguistics and has applications that could vastly improve understanding of how language is produced and comprehended by computers.
Work has also been done in making computers produce language in a more naturalistic manner. Using linguistic input from humans, algorithms have been constructed which are able to modify a system's style of production based on a factor such as linguistic input from a human, or more abstract factors like politeness or any of the five main dimensions of personality. This work takes a computational approach via parameter estimation
Estimation theory is a branch of statistics that deals with estimating the values of parameters based on measured empirical data that has a random component. The parameters describe an underlying physical setting in such a way that their val ...
models to categorize the vast array of linguistic styles we see across individuals and simplify it for a computer to work in the same way, making human–computer interaction
Human–computer interaction (HCI) is research in the design and the use of computer technology, which focuses on the interfaces between people ( users) and computers. HCI researchers observe the ways humans interact with computers and design ...
much more natural.
Text-based interactive approach
Many of the earliest and simplest models of human–computer interaction, such as ELIZA for example, involve a text-based input from the user to generate a response from the computer. By this method, words typed by a user trigger the computer to recognize specific patterns and reply accordingly, through a process known as keyword spotting.
Speech-based interactive approach
Recent technologies have placed more of an emphasis on speech-based interactive systems. These systems, such as Siri
Siri ( ) is a virtual assistant that is part of Apple Inc.'s iOS, iPadOS, watchOS, macOS, tvOS, and audioOS operating systems. It uses voice queries, gesture based control, focus-tracking and a natural-language user interface to answer ques ...
of the iOS operating system, operate on a similar pattern-recognizing technique as that of text-based systems, but with the former, the user input is conducted through speech recognition
Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the ma ...
. This branch of linguistics involves the processing of the user's speech as sound waves and the interpreting of the acoustics and language patterns for the computer to recognize the input.
Comprehension approaches
Much of the focus of modern computational linguistics is on comprehension. With the proliferation of the internet and the abundance of easily accessible written human language, the ability to create a program capable of understanding human language would have many broad and exciting possibilities, including improved search engines, automated customer service, and online education.
Early work in comprehension included applying Bayesian statistics to the task of optical character recognition, as illustrated by Bledsoe and Browing in 1959 in which a large dictionary of possible letters was generated by "learning" from example letters and then the probability that any one of those learned examples matched the new input was combined to make a final decision. Other attempts at applying Bayesian statistics to language analysis included the work of Mosteller and Wallace (1963) in which an analysis of the words used in ''The Federalist Papers
''The Federalist Papers'' is a collection of 85 articles and essays written by Alexander Hamilton, James Madison, and John Jay under the collective pseudonym "Publius" to promote the ratification of the Constitution of the United States. The ...
'' was used to attempt to determine their authorship (concluding that Madison most likely authored the majority of the papers).
In 1971 Terry Winograd developed an early natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
engine capable of interpreting naturally written commands within a simple rule-governed environment. The primary language parsing program in this project was called SHRDLU, which was capable of carrying out a somewhat natural conversation with the user giving it commands, but only within the scope of the toy environment designed for the task. This environment consisted of different shaped and colored blocks, and SHRDLU was capable of interpreting commands such as "Find a block which is taller than the one you are holding and put it into the box." and asking questions such as "I don't understand which pyramid you mean." in response to the user's input. While impressive, this kind of natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
has proven much more difficult outside the limited scope of the toy environment. Similarly, a project developed by NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeedi ...
called LUNAR was designed to provide answers to naturally written questions about the geological analysis of lunar rocks returned by the Apollo missions. These kinds of problems are referred to as question answering.
Initial attempts at understanding spoken language were based on work done in the 1960s and 1970s in signal modeling where an unknown signal is analyzed to look for patterns and to make predictions based on its history. An initial and somewhat successful approach to applying this kind of signal modeling to language was achieved with the use of hidden Markov models as detailed by Rabiner in 1989. This approach attempts to determine probabilities for the arbitrary number of models that could be being used in generating speech as well as modeling the probabilities for various words generated from each of these possible models. Similar approaches were employed in early speech recognition
Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the ma ...
attempts starting in the late 70s at IBM using word/part-of-speech pair probabilities.
More recently these kinds of statistical approaches have been applied to more difficult tasks such as topic identification using Bayesian parameter estimation to infer topic probabilities in text documents.
Applications
Applied computational linguistics is largely equivalent with natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
. Example applications for end users include speech recognition software, such as Apple's Siri feature, spellcheck tools, speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal languag ...
programs, which are often used to demonstrate pronunciation or help disabled people, and machine translation programs and websites, such as Google Translate.
Computational linguistics are also helpful in situations involving social media
Social media are interactive media technologies that facilitate the creation and sharing of information, ideas, interests, and other forms of expression through virtual communities and networks. While challenges to the definition of ''social me ...
and the Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a ''internetworking, network of networks'' that consists ...
, e.g., for providing content filters in chatrooms or on website searches,[ for grouping and organizing content through social media mining, document retrieval and clustering. For instance, if a person searches "red, large, four-wheeled vehicle," to find pictures of a red truck, the search engine will still find the information desired by matching words such as "four-wheeled" with "car".
Computational approaches are also important to support linguistic research, e.g., in ]corpus linguistics
Corpus linguistics is the study of a language as that language is expressed in its text corpus (plural ''corpora''), its body of "real world" text. Corpus linguistics proposes that a reliable analysis of a language is more feasible with corpora ...
[ or ]historical linguistics
Historical linguistics, also termed diachronic linguistics, is the scientific study of language change over time. Principal concerns of historical linguistics include:
# to describe and account for observed changes in particular languages
# ...
. As for the study of change over time, computational methods can contribute to the modeling and identification of language families[Bowern, Claire. "Computational phylogenetics." Annual Review of Linguistics 4 (2018): 281-296.] (see further quantitative comparative linguistics or phylogenetics), as well as the modeling of changes in sound and meaning.
Legacy
The subject of computational linguistics has had a recurring impact on popular culture:
* The Star Trek
''Star Trek'' is an American science fiction media franchise created by Gene Roddenberry, which began with the eponymous 1960s television series and quickly became a worldwide pop-culture phenomenon. The franchise has expanded into vario ...
franchise features heavily classical NLP applications, most notably machine translation
Machine translation, sometimes referred to by the abbreviation MT (not to be confused with computer-aided translation, machine-aided human translation or interactive translation), is a sub-field of computational linguistics that investigates t ...
( universal translator), natural language user interfaces and question answering.
* The 1983 film '' WarGames'' features a young computer hacker who interacts with an artificially intelligent supercomputer.
* A 1997 film, '' Conceiving Ada'', focuses on Ada Lovelace
Augusta Ada King, Countess of Lovelace ('' née'' Byron; 10 December 1815 – 27 November 1852) was an English mathematician and writer, chiefly known for her work on Charles Babbage's proposed mechanical general-purpose computer, the ...
, considered one of the first computer programmers, as well as themes of computational linguistics.
* '' Her,'' a 2013 film, depicts a man's interactions with the "world's first artificially intelligent operating system."
* The 2014 film ''The Imitation Game
''The Imitation Game'' is a 2014 American historical drama film directed by Morten Tyldum and written by Graham Moore, based on the 1983 biography '' Alan Turing: The Enigma'' by Andrew Hodges. The film's title quotes the name of the game ...
'' follows the life of computer scientist Alan Turing, developer of the Turing Test.
* The 2015 film '' Ex Machina'' centers around human interaction with artificial intelligence.
* The 2016 film '' Arrival'', based on Ted Chiang's Story of Your Life, takes a whole new approach of linguistics to communicate with advanced alien race called heptapods.
See also
* Artificial intelligence in fiction
Artificial intelligence is a recurrent theme in science fiction, whether utopian, emphasising the potential benefits, or dystopian, emphasising the dangers.
The notion of machines with human-like intelligence dates back at least to Samuel Butler' ...
* Collostructional analysis
* Computational lexicology
Computational lexicology is a branch of computational linguistics, which is concerned with the use of computers in the study of lexicon. It has been more narrowly described by some scholars (Amsler, 1980) as the use of computers in the study of '' ...
* ''Computational Linguistics'' (journal)
* Computational models of language acquisition
* Computational semantics
* Computational semiotics
* Computer-assisted reviewing
* Dialog systems
A dialogue system, or conversational agent (CA), is a computer system intended to converse with a human. Dialogue systems employed one or more of text, speech, graphics, haptics, gestures, and other modes for communication on both the input and o ...
* Glottochronology Glottochronology (from Attic Greek γλῶττα ''tongue, language'' and χρόνος ''time'') is the part of lexicostatistics which involves comparative linguistics and deals with the chronological relationship between languages.Sheila Embleton ( ...
* Grammar induction
Grammar induction (or grammatical inference) is the process in machine learning of learning a formal grammar (usually as a collection of ''re-write rules'' or '' productions'' or alternatively as a finite state machine or automaton of some kind) fr ...
* Human speechome project
* Internet linguistics
* Lexicostatistics
Lexicostatistics is a method of comparative linguistics that involves comparing the percentage of lexical cognates between languages to determine their relationship. Lexicostatistics is related to the comparative method but does not reconstruct a ...
* Natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to proc ...
* Natural language user interface
* Quantitative linguistics
* Semantic relatedness
* Semantometrics Semantometrics is a tool for evaluating research. It is functionally an extension of tools such as bibliometrics, webometrics, and altmetrics, but instead of just evaluating citations – which entails relying on outside evidence – it uses a sema ...
* Systemic functional linguistics #
*
Systemic functional linguistics (SFL) is an approach to linguistics, among functional linguistics, that considers language as a social semiotic system.
It was devised by Michael Halliday, who took the notion of system from J. R. Firth, hi ...
* Translation memory A translation memory (TM) is a database that stores "segments", which can be sentences, paragraphs or sentence-like units (headings, titles or elements in a list) that have previously been translated, in order to aid human translators. The translati ...
* Universal Networking Language
References
Further reading
*
* Steven Bird, Ewan Klein, and Edward Loper (2009). ''Natural Language Processing with Python''. O'Reilly Media. .
* Daniel Jurafsky and James H. Martin (2008). ''Speech and Language Processing'', 2nd edition. Pearson Prentice Hall. .
* Mohamed Zakaria KURDI (2016). ''Natural Language Processing and Computational Linguistics: speech, morphology, and syntax'', Volume 1. ISTE-Wiley. .
* Mohamed Zakaria KURDI (2017). ''Natural Language Processing and Computational Linguistics: semantics, discourse, and applications'', Volume 2. ISTE-Wiley. .
External links
Association for Computational Linguistics (ACL)
*
ACL Anthology of research papers
*
ACL Wiki for Computational Linguistics
CICLing annual conferences on Computational Linguistics
Computational Linguistics – Applications workshop
*
Language Technology World
The Research Group in Computational Linguistics
{{DEFAULTSORT:Computational Linguistics
Formal sciences
Cognitive science
Computational fields of study