The DeepL plugin included with Help+Manual uses DeepL's amazingly accurate artificial intelligence translation system to translate in both directions between the 25 currently supported languages:
Bulgarian, British English, American English, Chinese (simplified), Czech, Danish, Dutch, Estonian, Finnish, French, German, Greek, Hungarian, Italian, Japanese, Latvian, Lithuanian, Polish, Portuguese, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Turkish
It is very fast and works in a way that allows you to check the translations as you go and make any necessary corrections.
How to use the translation plugin
You can test the quality of DeepL translations directly on the DeepL website. Just visit the site and enter the text you want to translate. You'll be amazed at the quality of the results.
You can use DeepL free of charge in Help+Manual with a free API subscription that allows you to translate up to 500,000 characters of text per month. This is a great way to test it out, and it will also be easily enough for many smaller projects. Note however that the character count does include all the XML code, so it may be less than you expect.
If you need more text you can opt for the paid subscription, which is just €4.99 a month plus very reasonable volume fees. Either way, it is a tiny fraction of what translation normally costs.
Getting your Developer API key
You can get the free or paid Developer API key subscription directly on this page at the DeepL website:
Important: You must have a Developer API key, not any other type
You must use either a Developer API key (free or paid) to use DeepL with Help+Manual . Please do make sure that is the one you get, because other key types available on other pages on the DeepL site won't work.