quality:corruption, linguistic:paraphrasing, structural:reformatting, quality:correction
Western theory

Discussions of the theory and practice of translation reach back into antiquity and show remarkable continuities. The ancient Greeks distinguished between metaphrase (literal translation) and paraphrase. This distinction was adopted by English poet and translator John Dryden (1631–1700), who described translation as the judicious blending of these two modes of phrasing when selecting, in the target language, "counterparts," or equivalents, for the expressions used in the source language:

When appear... literally graceful, it were an injury to the author that they should be changed. But since... what is beautiful in one is often barbarous, nay sometimes nonsense, in another, it would be unreasonable to limit a translator to the narrow compass of his author's words: 'tis enough if he choose out some expression which does not vitiate the sense.

Dryden cautioned, however, against the license of "imitation", i.e., of adapted translation: "When a painter copies from the life... he has no privilege to alter features and lineaments..."

This general formulation of the central concept of translation— equivalence —is as adequate as any that has been proposed since Cicero and Horace, who, in 1st-century-BCE Rome, famously and literally cautioned against translating "word for word" (verbum pro verbo).

Despite occasional theoretical diversity, the actual practice of translation has hardly changed since antiquity. Except for some extreme metaphrasers in the early Christian period and the Middle Ages, and adapters in various periods (especially pre-Classical Rome, and the 18th century), translators have generally shown prudent flexibility in seeking equivalents —"literal" where possible, paraphrastic where necessary—for the original meaning and other crucial "values" (e.g., style, verse form, concordance with musical accompaniment or, in films, with speech articulatory movements) as determined from context.

In general, translators have sought to preserve the context itself by reproducing the original order of sememes, and hence word order —when necessary, reinterpreting the actual grammatical structure, for example, by shifting from active to passive voice, or vice versa. The grammatical differences between "fixed-word-order" languages (e.g. English, French, German) and "free-word-order" languages (e.g., Greek, Latin, Polish, Russian) have been no impediment in this regard. The particular syntax (sentence-structure) characteristics of a text's source language are adjusted to the syntactic requirements of the target language.

When a target language has lacked terms that are found in a source language, translators have borrowed those terms, thereby enriching the target language. Thanks in great measure to the exchange of calques and loanwords between languages, and to their importation from other languages, there are few concepts that are " untranslatable " among the modern European languages. A greater problem, however, is translating terms relating to cultural concepts that have no equivalent in the target language. For full comprehension, such situations require the provision of a gloss.

Generally, the greater the contact and exchange that have existed between two languages, or between those languages and a third one, the greater is the ratio of metaphrase to paraphrase that may be used in translating among them. However, due to shifts in ecological niches of words, a common etymology is sometimes misleading as a guide to current meaning in one or the other language. For example, the English actual should not be confused with the cognate French actuel ("present", "current"), the Polish aktualny ("present", "current," "topical", "timely", "feasible"), the Swedish aktuell ("topical", "presently of importance"), the Russian актуальный ("urgent", "topical") or the Dutch actueel ("current").

The translator's role as a bridge for "carrying across" values between cultures has been discussed at least since Terence, the 2nd-century-BCE Roman adapter of Greek comedies. The translator's role is, however, by no means a passive, mechanical one, and so has also been compared to that of an artist. The main ground seems to be the concept of parallel creation found in critics such as Cicero. Dryden observed that "Translation is a type of drawing after life..." Comparison of the translator with a musician or actor goes back at least to Samuel Johnson 's remark about Alexander Pope playing Homer on a flageolet, while Homer himself used a bassoon.

In the 13th century, Roger Bacon wrote that if a translation is to be true, the translator must know both languages, as well as the science that he is to translate; and finding that few translators did, he wanted to do away with translation and translators altogether.

The translator of the Bible into German, Martin Luther (1483–1546), is credited with being the first European to posit that one translates satisfactorily only toward his own language. L.G. Kelly states that since Johann Gottfried Herder in the 18th century, "it has been axiomatic" that one translates only toward his own language.

Compounding the demands on the translator is the fact that no dictionary or thesaurus can ever be a fully adequate guide in translating. The Scottish historian Alexander Tytler, in his Essay on the Principles of Translation (1790), emphasized that assiduous reading is a more comprehensive guide to a language than are dictionaries. The same point, but also including listening to the spoken language, had earlier, in 1783, been made by the Polish poet and grammarian Onufry Kopczyński.

The translator's special role in society is described in a posthumous 1803 essay by "Poland's La Fontaine ", the Roman Catholic Primate of Poland, poet, encyclopedist, author of the first Polish novel, and translator from French and Greek, Ignacy Krasicki:

ranslation... is in fact an art both estimable and very difficult, and therefore is not the labor and portion of common minds; should be by those who are themselves capable of being actors, when they see greater use in translating the works of others than in their own works, and hold higher than their own glory the service that they render their country.