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Example-based machine translation (EBMT) is a method of
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 ...
often characterized by its use of a bilingual corpus with
parallel text A parallel text is a text placed alongside its translation or translations. Parallel text alignment is the identification of the corresponding sentences in both halves of the parallel text. The Loeb Classical Library and the Clay Sanskrit Libr ...
s as its main knowledge base at run-time. It is essentially a translation by
analogy Analogy (from Greek ''analogia'', "proportion", from ''ana-'' "upon, according to" lso "against", "anew"+ ''logos'' "ratio" lso "word, speech, reckoning" is a cognitive process of transferring information or meaning from a particular subject ...
and can be viewed as an implementation of a
case-based reasoning In artificial intelligence and philosophy, case-based reasoning (CBR), broadly construed, is the process of solving new problems based on the solutions of similar past problems. In everyday life, an auto mechanic who fixes an engine by recallin ...
approach to
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 ...
.


Translation by analogy

At the foundation of example-based machine translation is the idea of translation by analogy. When applied to the process of human translation, the idea that translation takes place by analogy is a rejection of the idea that people translate sentences by doing deep linguistic analysis. Instead, it is founded on the belief that people translate by first decomposing a sentence into certain phrases, then by translating these phrases, and finally by properly composing these fragments into one long sentence. Phrasal translations are translated by analogy to previous translations. The principle of translation by analogy is encoded to example-based machine translation through the example translations that are used to train such a system. Other approaches to machine translation, including
statistical machine translation Statistical machine translation (SMT) is a machine translation paradigm where translations are generated on the basis of statistical models whose parameters are derived from the analysis of bilingual text corpora. The statistical approach contras ...
, also use bilingual corpora to learn the process of translation.


History

Example-based machine translation was first suggested by
Makoto Nagao was a Japanese computer scientist. He contributed to various fields: machine translation, natural language processing, pattern recognition, image processing and library science. He was the 23rd president of Kyoto University (1997–2003) and the ...
in 1984. He pointed out that it is especially adapted to translation between two totally different languages, such as English and Japanese. In this case, one sentence can be translated into several well-structured sentences in another language, therefore, it is no use to do the deep linguistic analysis characteristic of rule-based machine translation.


Example

Example-based machine translation systems are trained from bilingual parallel corpora containing sentence pairs like the example shown in the table above. Sentence pairs contain sentences in one language with their translations into another. The particular example shows an example of a ''minimal pair'', meaning that the sentences vary by just one element. These sentences make it simple to learn translations of portions of a sentence. For example, an example-based machine translation system would learn three units of translation from the above example: # ''How much is that'' X ''?'' corresponds to ''Ano X wa ikura desu ka.'' # ''red umbrella'' corresponds to ''akai kasa'' # ''small camera'' corresponds to ''chiisai kamera'' Composing these units can be used to produce novel translations in the future. For example, if we have been trained using some text containing the sentences: ''President Kennedy was shot dead during the parade.'' and ''The convict escaped on July 15th.'' We could translate the sentence ''The convict was shot dead during the parade.'' by substituting the appropriate parts of the sentences.


Phrasal verbs

Example-based machine translation is best suited for sub-language phenomena like
phrasal verb In the traditional grammar of Modern English, a phrasal verb typically constitutes a single semantic unit composed of a verb followed by a particle (examples: ''turn down'', ''run into'' or ''sit up''), sometimes combined with a preposition (e ...
s. Phrasal verbs have highly context-dependent meanings. They are common in English, where they comprise a verb followed by an
adverb An adverb is a word or an expression that generally modifies a verb, adjective, another adverb, determiner, clause, preposition, or sentence. Adverbs typically express manner, place, time, frequency, degree, level of certainty, etc., answering ...
and/or a
preposition Prepositions and postpositions, together called adpositions (or broadly, in traditional grammar, simply prepositions), are a class of words used to express spatial or temporal relations (''in'', ''under'', ''towards'', ''before'') or mark various ...
, which are called the
particle In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, from ...
to the verb. Phrasal verbs produce specialized context-specific meanings that may not be derived from the meaning of the constituents. There is almost always an ambiguity during word-to-word translation from source to the target language. As an example, consider the phrasal verb "put on" and its Hindustani translation. It may be used in any of the following ways: *Ram put on the lights. (Switched on) (Hindustani translation: ''Jalana'') *Ram put on a cap. (Wear) (Hindustani translation: ''Pahenna'')


See also

* Programming by example * Translation memory *
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 ...


References


Further reading

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External links


Cunei
- an open source platform for data-driven machine translation that grew out of research in EBMT, but also includes recent advances from the SMT field {{Approaches to machine translation Machine translation Machine translation, example-based