Robert Važan Jun 7, 2023 – Oct 8, 2024

Free automated translators for Slovak

This article is somewhat applicable to other languages, but I can only check quality of Slovak translations and that's what I will focus on. While translation from Slovak to English works almost perfectly, translation in the opposite direction, from English to Slovak, is needed more often and automated translators are far from perfect in that regard. You have to check their output and correct any errors in it. Individual translators differ mainly in how many mistakes they make. And no, Google Translate is not the best.

Update (October 2024): I now recommend LLMs for all translations between English ond Slovak. The technology has matured and LLMs are now clearly superior to specialized translation services listed in this article. If you prefer the old-fashioned services anyway, keep reading.

Let's first cover translations from Slovak to English, because they are done much more easily. I recommend using ChatGPT for this purpose, as it can be guided by instructions. If you don't like something in the translation, you simply say it, and ChatGPT will rewrite the entire translation with the desired modifications. ChatGPT has its drawbacks, mainly being very slow during peak times, so sometimes it's better to use Google Translate.

As mentioned before, translations from English to Slovak are full of errors, so it's important to use the right translator to minimize time spent on editing. I tested popular translators in a very unscientific way — by counting errors in the Slovak translation of one article. The article had a total of 377 words and included a lot of text that should not be translated (names, quotes, code), to test the overall intelligence of the translator.

Here are the best translators ranked by translation quality:

DeepL Translator - Translations are surprisingly good. Not only did I count the fewest errors (12), but the translated text actually sounded Slovak, thanks to several well-chosen stylistic details. The disadvantage is a stricter text length limit, but the translator automatically translates everything that fits within the limit, and you can obtain the rest of the translation by deleting the already translated part of the original text, which is minimal effort. A peculiarity of DeepL is its obsession with translating absolutely everything, including code, names, and quotes, which increased the total number of errors by another 11. However, since my sample text is relatively unusual in this regard, and a typical source text would not be affected by this flaw, I did not count these errors.
Google Translate - Popular but not the best. I counted 25 errors, more than twice as many as DeepL. Its advantage is a higher text length limit and more free features.
ChatGPT - ChatGPT is surprisingly good at translations. It performs best in the direction from Slovak to English. When translating from English to Slovak, it introduces many errors (I counted 30), both the usual stylistic errors and embarrassingly also grammatical errors, which is a big surprise for a language model with higher cognitive abilities. This is mostly true even for the paid version. ChatGPT is probably trained on a very small amount of Slovak texts. The main advantage of ChatGPT is the ability to guide the translation with instructions. However, these instructions do not help with the most common mistakes that ChatGPT currently makes, which is why I rank it below Google Translate. I tried hinting ChatGPT with the correct translation of another article, but it only made the output worse, probably because it exhausted its context window.
Bing Translator - Limited to paragraph-sized texts. If the limit is exceeded, Bing Translator fails with an error and it doesn't even attempt to translate what fits within the limit. This makes it so impractical, I did not even get to investigating quality of the translation.
LibreTranslate - This translator is interesting because it is open source, and you can have it installed for free on company server or even on your own computer and connect to it from open-source applications like Dialect. It is built on the open-source neural network OpenNMT. However, in the current version, the translation quality to Slovak is really tragic. Almost everything needs to be corrected. Nevertheless, if the translation quality improves in the future, we can look forward to unlimited free translations that work offline and respect privacy.

There are also many translators limited to sentence-sized texts, but since it doesn't make sense to measure accuracy on such short texts, I am not even enumerating them here.