HOME

TheInfoList




Computational linguistics is an
interdisciplinary Interdisciplinarity or interdisciplinary studies involves the combination of two or more academic disciplines into one activity (e.g., a research project). It draws knowledge from several other fields like sociology, anthropology, psychology, ...
field concerned with the computational modelling of
natural language In neuropsychology Neuropsychology is a branch of psychology. It is concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology often focus on ...
, 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 language A language is a structured system of communication Communication (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo ...

linguistics
,
computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application. Computer science is the study of computation, automation, a ...
,
artificial intelligence Artificial intelligence (AI) is intelligence Intelligence has been defined in many ways: the capacity for abstraction Abstraction in its main sense is a conceptual process where general rules and concept Concepts are defined as abstra ...

artificial intelligence
,
mathematics Mathematics (from Greek: ) includes the study of such topics as numbers (arithmetic and number theory), formulas and related structures (algebra), shapes and spaces in which they are contained (geometry), and quantities and their changes (cal ...
,
logic Logic is an interdisciplinary field which studies truth and reasoning. Informal logic seeks to characterize Validity (logic), valid arguments informally, for instance by listing varieties of fallacies. Formal logic represents statements and ar ...

logic
,
philosophy Philosophy (from , ) is the study of general and fundamental questions, such as those about Metaphysics, existence, reason, Epistemology, knowledge, Ethics, values, Philosophy of mind, mind, and Philosophy of language, language. Such questio ...

philosophy
,
cognitive science Cognitive science is the interdisciplinary Interdisciplinarity or interdisciplinary studies involves the combination of two or more academic discipline An academic discipline or academic field is a subdivision of knowledge that is Educ ...

cognitive science
,
cognitive psychology Cognitive psychology is the scientific study of mental process Cognition () refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses many aspects of intelle ...
,
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 human Humans (''Homo sapiens'') are the most abundant and widespread species In biology Biology is the natural science that studies life and living organisms, including their anatomy, ...
and
neuroscience Neuroscience is the scientific study of the nervous system In biology, the classical doctrine of the nervous system determines that it is a Complex system, highly complex part of an animal that coordinates its Behavior, actions and Sens ...

neuroscience
, among others.


Sub-fields and related areas

Traditionally, computational linguistics emerged as an area of
artificial intelligence Artificial intelligence (AI) is intelligence Intelligence has been defined in many ways: the capacity for abstraction Abstraction in its main sense is a conceptual process where general rules and concept Concepts are defined as abstra ...

artificial intelligence
performed by
computer scientist A computer scientist is a person who has acquired the knowledge of computer science, the study of the theoretical foundations of information and computation and their application. Computer scientists typically work on the theoretical side of c ...

computer scientist
s who had specialized in the application of computers to the processing of a
natural language In neuropsychology Neuropsychology is a branch of psychology. It is concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology often focus on ...
. With the formation of the
Association for Computational Linguistics Association may refer to: *Club (organization) A club is an voluntary association, association of people united by a common interest or goal. A service club, for example, exists for voluntary or charitable activities. There are clubs devoted t ...
(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 a subfield of , , and concerned with the interactions between computers and human language, in particular how to program computers to process and analyze large amounts of data. The goal is a computer capab ...
(NLP) and (human) language technology. These terms put a stronger emphasis on aspects of practical applications rather than theoretical inquiry and since the 2000s. 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 Theory of language is a topic from philosophy of languag ...
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 Linguistics is the scientific study of language, meaning that it is a comprehensive, systematic, objective, and precise study of language. Linguistics encompasses the analysis of every aspect of language, as well as the ...
(
parsing Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string String or strings may refer to: *String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other obj ...

parsing
) and
semantics Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another ...
, often grounded in formal logics and symbolic (
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 business services, knowledge-intensive activities that contribute to advance ...
) approaches. Areas of research that are studied by theoretical computational linguistics include: *
Computational complexity In computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application. Computer science is the study of , , ...
of natural language, largely modeled on
automata theory Automata theory is the study of abstract machines and automaton, automata, as well as the computational problems that can be solved using them. It is a theory in theoretical computer science. The word ''automata'' (the plural of ''automaton'') com ...

automata theory
, with the application of
context-sensitive grammar A context-sensitive grammar (CSG) is a formal grammar In formal language theory In mathematics, computer science, and linguistics, a formal language consists of string (computer science), words whose symbol (formal), letters are taken from an alp ...
and linearly bounded
Turing machine A Turing machine is a mathematical model of computation Mathematics (from Greek: ) includes the study of such topics as numbers (arithmetic and number theory), formulas and related structures (algebra), shapes and spaces in which they are ...

Turing machine
s. *
Computational semantics Computational semantics is the study of how to automate the process of constructing and reasoning with semantics, meaning representations of natural language expressions. It consequently plays an important role in natural language processing and c ...
comprises defining suitable logics for
linguistic meaning Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another ...
representation, automatically constructing them and reasoning with them Applied computational linguistics is dominated by
machine learning Machine learning (ML) is the study of computer algorithms that can improve automatically through experience and by the use of data. It is seen as a part of artificial intelligence. Machine learning algorithms build a model based on sample data ...

machine learning
, traditionally using
statistical methods Statistics is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data Data are units of information Information can be thought of as the resolution of uncertainty; it answers th ...

statistical methods
, since the mid-2010s by
neural networks A neural network is a network or circuit of 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 of biological neurons, or an ...

neural networks
: Socher et al. (2012) was an early
Deep Learning #REDIRECT Deep learning#REDIRECT Deep learning Deep learning (also known as deep structured learning) is part of a broader family of machine learning methods based on artificial neural networks with representation learning. Learning can be ...

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 a subfield of , , and concerned with the interactions between computers and human language, in particular how to program computers to process and analyze large amounts of data. The goal is a computer capab ...
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 of , either in , or s, conforming to the rules of a . The term ''parsing'' comes from Latin ''pars'' (''orationis''), meaning . The term has slightly different meani ...

parser
s for
natural language In neuropsychology Neuropsychology is a branch of psychology. It is concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology often focus on ...
s, or tasks such as
machine translation Machine translation, sometimes referred to by the abbreviation MT (not to be confused with Computer-assisted translation, computer-aided translation, machine-aided human translation or Interactive machine translation, interactive translation), is ...
(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 dichothomy 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 Interdisciplinarity or interdisciplinary studies involves the combination of two or more academic discipline An academic discipline or academic field is a subdivision of knowledge that is Educa ...

speech recognition
and
speech synthesis Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech computer or speech synthesizer, and can be implemented in software or Computer hardware, hardware products. A text-to-speech ...
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 In linguistics Linguistics is the scientific study of language A language is a structured system of communication Communication ...
, 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 Language change is variation over time in a language A language is a structured system of communication used by humans, including s ...
/
glottochronology Glottochronology (from Attic Greek Attic Greek is the Greek language, Greek dialect of the regions of ancient Greece, ancient region of Attica, including the ''polis'' of classical Athens, Athens. Often called classical Greek, it was the prestige ...
.


Origins

Computational linguistics is often grouped within the field of
artificial intelligence Artificial intelligence (AI) is intelligence Intelligence has been defined in many ways: the capacity for abstraction Abstraction in its main sense is a conceptual process where general rules and concept Concepts are defined as abstra ...

artificial intelligence
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 (from the Ancient Greek, Greek wikt:en:ἀριθμός#Ancient Greek, ἀριθμός ''arithmos'', 'number' and wikt:en:τική#Ancient Greek, τική wikt:en:τέχνη#Ancient Greek, έχνη ''tiké échne', 'art' or 'cr ...
(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 p ...
and
glottochronology Glottochronology (from Attic Greek Attic Greek is the Greek language, Greek dialect of the regions of ancient Greece, ancient region of Attica, including the ''polis'' of classical Athens, Athens. Often called classical Greek, it was the prestige ...
, 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 Locus (plural loci) is Latin for "place". It may refer to: Entertainment * Locus (comics), a Marvel Comics mutant villainess, a member of the Mutant Liberation Front * Locus (maga ...
, 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-assisted translation, computer-aided translation, machine-aided human translation or Interactive machine translation, interactive translation), is ...
(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 and , an algorithm () is a finite sequence of , computer-implementable instructions, typically to solve a class of problems or to perform a computation. Algorithms are always and are used as specifications for performing s, , , and other ...

algorithm
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 Linguistics is the scientific study of language, meaning that it is a comprehensive, systematic, objective, and precise study of language. Linguistics encompasses the analysis of every aspect of language, as well as the ...
of both languages, including both
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology) In archaeology, morphology is the study of the shape of Artifact (archaeology), artefacts and ecofacts. Morphology is a major consid ...
(the grammar of word forms) and
syntax In linguistics Linguistics is the scientific study of language, meaning that it is a comprehensive, systematic, objective, and precise study of language. Linguistics encompasses the analysis of every aspect of language, as well as the ...

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 Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another ...
and the
lexicon A lexicon is the vocabulary A vocabulary is a set of familiar words In linguistics, a word of a spoken language can be defined as the smallest sequence of phonemes that can be uttered in isolation with semantic, objective or pragmatics, pra ...

lexicon
(or 'vocabulary'), and even something of the
pragmatics In linguistics Linguistics is the scientific study of language, meaning that it is a comprehensive, systematic, objective, and precise study of language. Linguistics encompasses the analysis of every aspect of language, as well as the m ...
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 deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application. Computer science is the study of computation, automation, a ...
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.


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 175px, Babies begin babbling around 5-7 months of age Bab ...
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 A language is a structured system of communication Communication (from Latin Latin (, or , ) is a classical language be ...
, human 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 The origin of language (spoken and signed, as well as language-related technological systems such as writing), its relationship with human evolution, and its consequences have been subjects of study for centuries. Scholars wishing to study the ...
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), are computing systems vaguely inspired by the biological neural networks that constitute animal brains. An ANN is based on a collection of connected units or nod ...

artificial neural network
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. 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 (e.g.). However, his best-known definition is ...
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 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 The Indo-European languages are a language family A language is a structured system of communication used by humans, including speech ( spoken language), g ...

English language
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 annotated, annotates syntactic or semantic sentence (linguistics), sentence structure. The construction of parsed corpora in the early 1990s revolutionized computational linguistics, which be ...
. 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 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 Linguistics is the scientific study of language, meaning that it is a comprehensive, systematic, objective, and precise study of language. Linguistics encompasses the analysis of every aspect of language, as well as the ...
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 formIn 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 (computer science), production rules are of the form: : ''A'' → ''BC'',   or : ''A'' → ...
) 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 Conversation is interactive communication Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with") is "an apparent answer to the painful d ...

discourse
. 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 English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, which has eventually become the World language, leading lan ...

English
as well as other languages, such as
Japanese Japanese may refer to: * Something from or related to Japan Japan ( ja, 日本, or , and formally ) is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or ...

Japanese
. Using computational methods, Japanese sentence corpora were analyzed and a pattern of log-normality 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, 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 A mathematician is someone who uses an extensive knowledge of mathematics Mathematics (from Greek: ) includes the study of such topics as numb ...

Alan Turing
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 A hypothesis (plural hypotheses) is a proposed explanation An explanation is a set of statements usually constructed to describe a set of facts which clarifies the ...
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 Alan Mathison Turing (; 23 June 1912 – 7 June 1954) was an English mathematician A mathematician is someone who uses an extensive knowledge of mathematics ...
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 or ELIZA may refer to: * Eliza (given name) Eliza is a feminine given name, a variation of the name Elizabeth (given name), Elizabeth. Etymology The name first developed as a diminutive of Elizabeth (given name), Elizabeth in the 16th centu ...
program developed by
Joseph Weizenbaum Joseph Weizenbaum (8 January 1923 – 5 March 2008) was a German American German Americans (german: Deutschamerikaner, ) are Americans who have full or partial Germans, German ancestry. With an estimated size of approximately 43 million in 20 ...

Joseph Weizenbaum
at
MIT Massachusetts Institute of Technology (MIT) is a private land-grant research university A research university is a university A university ( la, universitas, 'a whole') is an educational institution, institution of higher education, hi ...
in 1966. The program emulated a Rogerian
psychotherapist Psychotherapy (also psychological therapy or talking therapy) is the use of psychological Psychology is the scientific Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of T ...
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 wordsme", 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, several models have been compared, including
hidden Markov models Hidden Markov Model (HMM) is a statistical Statistics is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data Data are units of information Information can be thought of as ...
, 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: Common uses * of or related to Germany * Germans, Germanic ethnic group, citizens of Germany or people of German ancestry * For citizens of Germany, see also German nationality law * German language The German la ...

German
and
French French (french: français(e), link=no) may refer to: * Something of, from, or related to France France (), officially the French Republic (french: link=no, République française), is a transcontinental country This is a list of co ...

French
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 Statistical parameter, parameters based on measured empirical data that has a random component. The parameters describe an underlying physical setting in such ...
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 Computing, computer technology, which focuses on the Interface (computing), interfaces between people (user (computing), users) and computers. HCI researchers observe th ...
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 remote control In electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses ac ...

Siri
of the
iOS iOS (formerly iPhone OS) is a mobile operating system A mobile operating system is an operating system An operating system (OS) is system software System software is software designed to provide a platform for other software. Examples o ...

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 Interdisciplinarity or interdisciplinary studies involves the combination of two or more academic discipline An academic discipline or academic field is a subdivision of knowledge that is Educa ...

speech recognition
. 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 Pseudonym, collective pseudonym "Publius" to promote the History of the United States Constitution, ratifica ...
'' was used to attempt to determine their authorship (concluding that Madison most likely authored the majority of the papers). In 1971
Terry Winograd Terry Allen Winograd (born February 24, 1946) is an American professor of computer science at Stanford University, and co-director of the Stanford Human–Computer Interaction Group. He is known within the philosophy of mind and artificial intell ...
developed an early
natural language processing Natural language processing (NLP) is a subfield of , , and concerned with the interactions between computers and human language, in particular how to program computers to process and analyze large amounts of data. The goal is a computer capab ...
engine capable of interpreting naturally written commands within a simple rule-governed environment. The primary language parsing program in this project was called
SHRDLU SHRDLU was an early natural-language understanding Natural-language understanding (NLU) or natural-language interpretation (NLI) is a subtopic of natural-language processing in artificial intelligence that deals with machine reading comprehens ...
, 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 a subfield of , , and concerned with the interactions between computers and human language, in particular how to program computers to process and analyze large amounts of data. The goal is a computer capab ...
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 A regulatory agency or regulatory authority, is a Public benefit corporation Public-benefit corporation is a term that has different meanings in differen ...

NASA
called
LUNAR Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * Lunar (series), ''Lunar'' (series), a series of video games * Lunar (song), "Lunar" (song), by David Guetta * "Lunar", a song by Priestess f ...
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 Interdisciplinarity or interdisciplinary studies involves the combination of two or more academic discipline An academic discipline or academic field is a subdivision of knowledge that is Educa ...

speech recognition
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 a subfield of , , and concerned with the interactions between computers and human language, in particular how to program computers to process and analyze large amounts of data. The goal is a computer capab ...
. 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 computer or speech synthesizer, and can be implemented in software or Computer hardware, hardware products. A text-to-speech ...
programs, which are often used to demonstrate pronunciation or help the disabled, and machine translation programs and websites, such as Google Translate. Computational linguistics are also helpful in situations involving social media and the Internet, 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 In linguistics Linguistics is the scientific study of language A language is a structured system of communication Communication ...
or
historical linguistics Historical linguistics, also termed diachronic linguistics, is the scientific study of language change Language change is variation over time in a language A language is a structured system of communication used by humans, including s ...
. As for the study of change over time, computational methods can contribute to the modeling and identification of language familiesBowern, Claire. "Computational phylogenetics." Annual Review of Linguistics 4 (2018): 281-296. (see further Quantitative_comparative_linguistics, 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 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-assisted translation, computer-aided translation, machine-aided human translation or Interactive machine translation, interactive translation), is ...
(universal translator), Natural-language user interface, 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, considered one of the first computer programmers, as well as themes of computational linguistics. * ''Her (film), Her,'' a 2013 film, depicts a man's interactions with the "world's first artificially intelligent operating system." * The 2014 film ''The Imitation Game'' follows the life of computer scientist Alan Turing, developer of the Turing Test. * The 2015 film ''Ex Machina (film), Ex Machina'' centers around human interaction with artificial intelligence. * The 2016 film ''Arrival (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 * Collostructional analysis * Computational lexicology * Computational Linguistics (journal), ''Computational Linguistics'' (journal) * Computational models of language acquisition *
Computational semantics Computational semantics is the study of how to automate the process of constructing and reasoning with semantics, meaning representations of natural language expressions. It consequently plays an important role in natural language processing and c ...
* Computational semiotics * Computer-assisted reviewing * Dialog systems * Glottochronology * Grammar induction * Human speechome project * Internet linguistics * Lexicostatistics * Natural language processing * Natural language user interface * Quantitative linguistics * Semantic relatedness * Semantometrics * Systemic functional linguistics * Translation memory * 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 Computational linguistics, Subfields of computer science Formal sciences Cognitive science Computational fields of study