CAT software has nothing to do with cats (although many translators also have cats). CAT is the acronym of Computer-Assisted Translation. It is not the same as Machine Translation (or MT), although several CAT tools also include MT components.
Computer-assisted translation programs were created to help humans translate documents. Each software has different features but most have (a) utilities or processes that increase productivity and consistency in translation, (b) the ability to translate from a large variety of file formats, and (c) translation memory and terminology management.
Translation Memory and Terminology Management
The most important feature is translation memory management. A translation memory is simply a database where segments of the document in two (or more) languages are stored. A segment is usually one sentence. The linguist translates the segment and then both source text and translation are saved in the translation memory. The next time an identical or similar segment is found, the software automatically produces the translation previously created. The translator can then confirm, edit or reject the proposed translation. This is extremely useful in documents where segments are often repeated, such as technical documents.
Translation memory entries can also be used in other documents and not just the document where they were created. This can considerably speed up a translation with lots of repetitions and ensure consistency across one or more documents.
Thanks to advances in AI and machine learning, some CAT tools can provide good suggestions even for “fuzzy matches”, i.e. segments that are somewhat but not very similar to segments in the memory. Nevertheless, until AI develops to the point of comprehending language, a human must always check the quality of the translations offered by CAT software.
Terminology management works similar. Once a term has been translated, it is quick and easy to retrieve the translation the next time that the term appears. Translators can create multilingual glossaries for future reference. This also helps save time and avoid inconsistencies or errors.
Other CAT Features
CAT programs have various automated quality-assurance checks. These are very useful because computers are simply better than humans at spotting minor errors like spelling, punctuation or syntax errors. Proofreading by a human is still necessary but errors can be eliminated.
Another advantage of CAT tools is that they facilitate teamwork. Thanks to the translation memory management tools and other complementary tools like document alignment, it is easier for a team of translators to work on a set of documents without sacrificing consistency. This is of crucial importance for long, complex documents or documents that need frequent updates or other changes.
When a document has been translated using a CAT application, the translator can export the translation in the original file format or a variety of other formats (e.g. side-by-side bilingual text). The variety of working formats ensures that a translator does not need the application opening a proprietary file type. For instance, the translator can work on an Adobe InDesign file without owning the InDesign software or knowing how to use it.
Machine Translation (MT) Features
Some of the more advanced CAT programs also offer MT components. These vary in quality and usefulness, depending on the languages used and the subject of the source materials. In addition, MT can be a handicap for inexperienced translators who may be tempted to rely on MT-generated translations.
Which CAT Software?
The CAT tools most professionals prefer are SDL Trados, memoQ and Wordfast. They are powerful, expensive and have a steep learning curve and so they are only really useful to professional translators. SDL Trados is considered the industry standard (and the CAT tool I prefer at the moment) but it is arguably the least user-friendly. Each program has advantages and drawbacks but they all work well with each other.
There are also some web-based CAT tools like Smartcat and MateCat which offer basic CAT features at a much lower price. Professional translators may have one or more of these tools and select the tool best suited to the project they are working on.
Does a Professional Translator Need CAT Software?
It depends on how you define “need”. For centuries people translated materials without CAT software or computers. But with the advent of word-processing and, more recently, CAT software and online tools, a professional will want to use the tools that make her job easier and her clients happier.
In many cases, using CAT is a necessity. A technical translator working with large companies or translation agencies will certainly need many of the functionalities offered by CAT. As a lawyer-linguist working with complex language and long documents, I find that CAT speeds up my process and helps eliminate errors. I also find the terminology management tools especially helpful.
A literary translator would need way fewer functionalities. Nevertheless, a simple CAT application that allows her to see the source text while translating the target text is indispensable. In summary, the time, effort and cost involved when a professional starts using CAT tools is almost always well spent.