The English word "translation" derives from the Latin word translatio, which comes from trans, "across" + ferre, "to carry" or "to bring" (-latio in turn coming from latus, the past participle of ferre). Thus translatio is "a carrying across" or "a bringing across": in this case, of a text from one language to another.
Translation must take into account constraints that include context, the rules of grammar of the two languages, their writing conventions, and their idioms. A common misconception is that there exists a simple word-for-word correspondence between any two languages, and that translation is a straightforward mechanical process. A word-for-word translation does not take into account context, grammar, conventions, and idioms. Owing to the demands of business documentation consequent to the Industrial Revolution that began in the mid-18th century, some translation specialties have become formalized, with dedicated schools and professional associations. The demand in the translating field is greater than ever before. Many translators work as freelancers and others are employed by international organizations as well as government agencies. Nonprofit and religious organizations also hire or contract the services of translators for document translation. Individuals who work as translators are highly intellectual.
Interpreting and translation are two closely related linguistic disciplines. Yet they are rarely performed by the same people. The difference in skills, training, aptitude and even language knowledge are so substantial that few people can do both successfully on a professional level.
Interpreting, just like translation, is fundamentally the art of paraphrasing—the interpreter listens to a speaker in one language, grasps the content of what is being said, and then paraphrases his or her understanding of the meaning using the tools of the target language. However, just as you cannot explain a thought to someone if you did not fully understand that thought, neither can you translate or interpret something without mastery of the subject matter being relayed.
Both translation and interpretation (sometimes abbreviated as T + I) require superior language ability in at least two languages. That may seem like a given, but in fact there are many working translators whose language skills are not up to the task. You can usually recognize these unqualified translators by extremely low rates, and also by wild claims about being able to translate any language and subject.