Once an article has been translated the article is stored locally. This means that you can review and polish articles post-translation and reduces the cost of the translations.
Currently translates Articles and Categories, however it has been constructed in such a way that other components could potentially be added in the future.
You will need a DeepL API key. Cheapest currently is the 4.99€ Developer key.
DeepL currently supports English, German, French, Spanish, Dutch, Italian, Polish and Russian.
Once an article has been translated, new translations are associated with the original article through the Joomla language associations feature, and you can assign the new articles to your category of choice. I recommend that you create first your categories and install all relevant languages BEFORE you start the translation process.
There are a few things todo, such as recognising missing translations (e.g. a new language has been added to the DeepL service after the original article was first translated). If the component proves popular then I'll explore this further.