To configure permanently your language settings, go to Tools
>Options
, Language Settings
>Languages
. If you don’t check For the current document only, your preference will be stored in your user profile and made available for all your future documents.
To show the community your question has been answered, click the ✓ next to the correct answer, and “upvote” by clicking on the ^ arrow of any helpful answers. These are the mechanisms for communicating the quality of the Q&A on this site. Thanks!
In case you need clarification, edit your question (not an answer) or comment the relevant answer.
PS: your answer looks like a semi-answer (your mention of Tools
>Language
>For xxx
>…
) in that it affects only the current document. I’m wondering it it wouldn’t be better placed in a comment under your question. If you agree, you have an More link/menu with a “Repost as comment” command (from memory, because only the owner of the answer can see it).