Contrary to popular belief, there is no computer program which can automatically translate an entire text with one push of the button. Scientists have been trying to develop such a program for well over fifty years, but it seems unlikely that they will succeed in our lifetime!
'Translation tools' are quite simply software programs which assist the translation process: nothing more and nothing less. The two main technologies in use are MT (Machine Translation) and CAT (Computer-Aided Translation).
MT applications do attempt to translate an entire document, with varying results. Sometimes a machine translation from French or German into English can be passable, or at least readable (although the output will still require review and correction by a human translator). If the target language is Dutch, the results are always disappointing. Several MT applications are available free of charge online. They include FreeTranslation, InterTran, Reverso, and Google Translate.
CAT applications divide the text up into segments, perhaps a sentence or a paragraph at a time, and then try to find identical or similar passages in a database of previous translations. The market leader in CAT packages is SDL Trados Studio (which is our personal favourite), although Wordfast, Déjà Vu, memoQ and Memsource are also popular.
A CAT tool stores text segments (words, phrases, sentences or paragraphs) in structured databases known as 'translation memories', whereupon a translator can immediately see whether a term or phrase has been used before and can decide whether it would be appropriate to use it again this time. This can speed up the production process, especially for 'standard' documents such as technical manuals, but the greatest advantage is that it guarantees the consistent use of terminology.
The standard file format for translation memories is TMX. All the major CAT packages can exchange compatible TMX translation memories.