
Computer-Aided Translation Is Not Machine Translation
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Computer-aided translation is often seen as machine translation by mistake, although these are two different services. In this post, I go deeper into this topic as I want to draw your attention to the fact that computer-aided translation is not machine translation.
Let’s start with the basic difference between these two. Machine translation is done by a machine, while computer-aided translation is done by a human.
What is machine translation
Machine translation (MT) is a translation done by a machine leveraging algorithms, e.g., Google Translate, DeepL or Quillbot. It is a 100% automated process, i.e., it doesn’t include human intervention. You get the result really fast, but what you receive is often a word-by-word, out-of-context translation. Why is that?
First, because machines don’t recognize–nor translate accurately–idiomatic expressions, puns, jokes, colloquial language, etc. You can imagine what consequences for your business may have using machine translation if these elements are important in your content. It’s like picking a random word definition from a dictionary and hoping it’s correct in a given context.
Second, machines don’t take cultural aspects into account either.
✅ Of course, there are types of documents that can be translated quite well by a machine. These are, for example, technical, legal, or governmental ones. Their structure is simple, the word order repeats, and there is no colloquial language.
❌ But in case of marketing materials or literature–content that requires creativity–machine translation will do more harm than good.
It’s true that machine translation has rapidly developed in the last few years and is getting more and more accurate. However, it will take a long time–if ever–until it becomes as good as human translation.

What is computer-aided translation
You already know what machine translation is, so let’s move on to computer-aided translation.
Computer-aided translation or computer-assisted translation is sometimes called “machine-aided translation.”
❗ But IT IS NOT machine translation, as the latter name may suggest.
It is 100% done by a human using their language and translation skills, and leveraging a computer-aided translation tool, a CAT tool, in short.
What is a CAT tool
A CAT tool is software that assists us, translators in the translation process. Assists us, NOT TRANSLATES FOR US. What does it mean? It simply allows us to focus on what we do best, i.e., translate, while it “takes care of” the document layout and text formatting. How is it possible? CAT tools work on the text, words precisely. As a result, this is the only part of the document that changes. What you receive is the exact document you sent to a translator, but translated. It looks as if the text in a target language was inserted in place of the source text (text in a source language).
See the examples below.


CAT tools also help translators to ensure terminology consistency by creating translation memories and term bases. It is extremely useful if you need tons of similar content / content of the same field translated. Two most popular CAT tools are Trados and memoQ. I use Trados 2021.
(More on this topic in a separate post soon.)
Coming back to comparing machine translation and computer-aided translation…
Computer-aided translation is done by a human, so it’s not a word-by-word translation. A text is translated in context, and all the idiomatic expressions, jokes, puns, etc. are translated accurately. Cultural aspects of both languages are also taken into account.
The second pair of eyes rule
Moreover, two independent translators will usually work on your text, as there’s the so-called second pair of eyes rule in the translation industry. It means that the text is translated by one translator, and then proofread by another. Such process guarantees delivering a high-quality translation.
“So the first translator is not good enough?” you may think. Of course they are good enough. The thing is we, translators are just humans. Although we do review the translation before sending it to you, after working for many hours, we may not notice it due to eye fatigue. A fellow translator comes in handy then. They double-check that there are no typos, no information is missing, and that all is translated accurately. In some cases, they also come up with more sophisticated ideas for translating a term or expression.

Computer-aided translation vs. machine translation. What costs more
When you’re running a business, the final effect is what matters the most. However, money plays an important role, too. When your budget is low, you may feel tempted to use machine translation. Well, is it worth it?
Regarding the costs, you may say that you pay twice in both cases. In the case of machine translation, you pay for a translation and post-editing, and in the case of computer-aided translation, you pay for a translation and proofreading. True, except for a few “buts.”
1. The costs may not equal.
2. The quality of machine translation can’t equal the quality of human translation–and this is the biggest difference between computer-aided translation and machine translation.
3. Even if you hire a translator to post-edit your machine translation, i.e., polish and adapt it to the target audience (the service is called machine translation post-editing (MTPE)), the quality of the translation can be so bad that it’ll be better to do it from scratch.
4. For the reasons mentioned above and at the outset, translating a text in a machine and post-editing it may take longer than translating and proofreading it.
Recap, or which translation is better
Long story short, not choosing machine translation in case of specialized texts will save you stress, time and money. In particular, if you need your marketing materials translated / transcreated. Such content often contains puns, jokes, proverbs, idioms, and colloquial language. These need to be translated accurately, and cultural aspects also need to be taken into account. Machines can’t do that.
I hope it clarifies the differences between machine translation and computer-aided translation (translation done in a CAT tool). If you have any doubts or questions, feel free to comment the post or contact me.
QUESTION: If you translate your marketing content, what is your process like? Do you do machine translation on your own and hire a post-editor? Or do you hire a translator / translation agency to handle the whole process for you?
Dorota
Linguist and translator with 4 years of experience. A passionate photographer and traveler. I like meeting new people from all around the world and knowing their culture. I graduated from 3 different universities in Poland and one in Spain. At przeTŁUMACZ Dorota Oleś, I offer into-Polish translation services of English and Spanish marketing content, mainly related to sports and fashion. I also run a blog on which I share my insights and knowledge as a translator and linguist.