Interpreters and translators convert information from one language to another. Interpreters work in spoken or sign language, translators in written language.

Interpreters and translators typically do the following:

Interpreters and translators aid communication by converting information from one language into another. Although some people do both, interpreting and translating are different professions: interpreters deal with spoken words, translators with written words.

Interpreters convert information from one spoken language into another—or, in the case of sign language interpreters, between spoken language and sign language. Interpreters must usually be fluent speakers or signers of both languages because they communicate back and forth among the people who do not share each other's language.

There are two modes of interpreting: simultaneous and consecutive.

Simultaneous interpreting requires interpreters to listen or watch and speak or sign at the same time someone is speaking or signing. Simultaneous interpreting requires a high level of concentration. For that reason, simultaneous interpreters usually work in pairs, each interpreting for about 20 to 30 minutes and then resting while the other interprets. Simultaneous interpreters are often familiar with the subject matter so they can anticipate the end of a speaker's sentences.

In contrast, consecutive interpreting begins only after the speaker has said or signed a group of words or sentences. Consecutive interpreters often take notes while listening to or watching the speakers, so they must develop some type of notetaking or shorthand system.

Translators convert written materials from one language into another. The goal of a translator is to have people read the translation as if it were the original. To do that, the translator must be able to write sentences that flow as well as the original did while keeping the ideas and facts of the original accurate. Translators must consider any cultural references, including slang, and other expressions that do not translate literally.

Translators must read the original language fluently but may not need to speak it fluently. They usually translate only into their native language.

Nearly all translation work is done on a computer, and translators receive and submit most assignments electronically. Translations often go through several revisions before becoming final.

Interpreters’ and translators’ services are needed in a number of subject areas. Although these workers often do not specialize in any particular field or industry, many focus on one area of expertise.  

The following are examples of occupational specialties:

Health or medical interpreters and translators typically work in healthcare settings and help patients communicate with doctors, nurses, and other medical staff. Both interpreters and translators must have a strong grasp of medical terminology and the common words for those medical terms in both languages.

Health or medical interpreters must also have sensitivity to participate in patients' personal situations with healthcare providers.

Health or medical translators don't usually have the same level of personal interaction with patients and providers that interpreters do. They primarily convert information brochures, materials that patients must read and sign, and website information from one language to another.

Legal or judiciary interpreters and translators typically work in courts and other legal settings. At hearings, arraignments, depositions, and trials, they help people who have limited English proficiency. They must understand legal terminology. Many court interpreters must sometimes read documents aloud in a language other than that in which they were written, a task known as sight translation.

Literary translators rewrite journal articles, books, poetry, and short stories from one language into another language. They strive to keep the author's tone and style as well as meaning. Whenever possible, literary translators work closely with authors to capture their intended meaning and literary characteristics.

Localization translators adapt text for a product or service from one language into another. Localization specialists strive to make it appear as though the product originated in the country where it will be sold. They must know not only both languages, but they must also understand the technical information they are working with and must understand the culture of the people who will be using the product or service.

Localization may include adapting Internet sites, marketing materials, instruction manuals, and other publications. Usually, these are related to products and services in manufacturing and other business sectors.

Localization may be helped by computer-assisted translation, where a computer program develops an early draft of a translation for the localization translator to work with. Also, translators may use computers to compare previous translations with current assignments.

Sign language interpreters help people who are deaf or hard of hearing and people who can hear communicate with each other. Sign language interpreters must be fluent in English and in American Sign Language (ASL), which combines signing, finger spelling, and specific body language. ASL is a separate language from English with its own grammar.

Some interpreters specialize in other forms of interpreting for people who are deaf or hard of hearing.

Some people who are deaf or hard of hearing lip-read English instead of signing in ASL. Interpreters who work with these people do "oral interpretation," mouthing speech silently and very carefully so their lips can be read easily. They may also use facial expressions and gestures to help the lip-reader understand.

Other specialties include using cued speech, which uses hand shapes placed near the mouth to give lip-readers more information; signing exact English; and tactile signing, which is interpreting for people who are blind as well as deaf by making hand signs into the deaf-blind person's hand.

Guide or escort interpreters accompany either U.S. visitors abroad or foreign visitors in the United States to ensure that they are able to communicate during their stay. These specialists interpret informally and on a professional level. Frequent travel for these workers is common.

Conference interpreters work at conferences that have non-English-speaking attendees. The work is often in the field of international business or diplomacy, although conference interpreters can interpret for any organization that works with speakers of foreign languages. Employers prefer high-level interpreters who have the ability to translate from at least two languages into one native language—for example, the ability to interpret from Spanish and French into English. For some positions, such as those with the United Nations, this qualification is required.

Conference interpreters often do simultaneous interpreting. People at the conference who do not understand the language of the speaker wear earphones tuned to the interpreter who speaks the language they want to hear. The interpreter listens to a bit of the speaker's talk and then translates that bit. Simultaneous interpreters must be able to listen to the next bit the speaker is saying while translating the previous bit of what the speaker said.

Medical transcriptionists listen to voice recordings that physicians and other health professionals make and convert them into written reports. They interpret medical terminology and abbreviations in preparing patients’ medical histories, discharge summaries, and other documents. The documents they produce become part of a patient’s permanent file.

Medical transcriptionists typically do the following:

Medical transcriptionists use audio playback equipment, often including a headset and foot pedal—to control the recording playback speed—that are connected to their computer. They use word-processing and other specialized software, as well as medical reference materials as needed.

To do their work, medical transcriptionists must become familiar with medical words, anatomy and physiology, diagnostic procedures, pharmacology, and treatment assessments. Their ability to understand and correctly transcribe what the health professional has said is critical to reducing the chance that patients will get ineffective or even harmful treatments. They are part of the team that ensures high-quality patient care.

Medical transcriptionists who work in doctors’ offices may have other duties, such as answering phones or greeting patients.