Hi Arnoud, From the documentation: "TextTranslation requires internet connectivity and uses external services that require Service Credits." I wrote this package to help manage one's funds on translating notebooks:
http://community.wolfram.com/groups/-/m/t/1313456
For a whole notebook, a user might also consider saving the notebook as html and see what Google Translate produces. But then it may be a hassle to go back to a notebook again.
