Machine translation happens when computerised systems attempt to automate the translation process from one human language into another. There is a difference between human-aided machine translation and machine-aided human translation:

• Machine-aided human translation happens when human translators use translation tools or software to help them with their translation work.
• Human-aided machine translation is when tools or software simulate the process of human translation with limited human intervention.

Translation memories are large databases of translated texts/units, which may include words, collocations, fixed expressions, and even short sentences. These units are activated (recalled or made available) automatically during the translation process. If relevant, the translator then merely must insert the unit into a text, in lieu of translating a whole piece of text from scratch. Translation memories are often used for the translation of technical documents, or documents with similarities to other documents. In the latter instances, translation memories help to avoid tedious repetition. Well-known systems working with translation memories include Trados^®, DejaVu^®, Wordfast^® and OmegaT^®.

Machine translation systems (a.k.a. ‘automatic translation software’) differ from translation memories in the sense that the translation process is fully automated, with no human intervention involved. An end-user usually pastes his/her text into the system, selects the language pairs, clicks on a button, and a full translation is provided forthwith. It is very important to note, however, that human intervention is required in text revision (‘post-editing’) of the machine translated results. Machine translation systems can be very inaccurate as context-sensitive translation through software is extremely difficult to accomplish. Technology can therefore never replace human translators, but rather contributes to an increase in the quantity and quality of translation work.