@pheggas I do not think that this option should go directly to the Opera. You can always use an extension (both from the Opera add-ons and Chrome Web Store add-ons). Or use my proprietary solution
In Opera, add a new search engine with the address:
Of course, "%s" must stay, because here "searchable" text will be inserted. Only change "pl" to the abbreviation of your language. However, thanks to the "#auto" you will not have to set the language of the source text, only Google Translator will search for it automatically.
In any case, now just select a piece of text, display the context menu and "search" it with the help of this "search engine". I immediately warn you that if you select too much text, it will be cut off in Google Translate. But the point is to mark literally a dozen sentences.
If you do not like/dislike Google Translate then it seems to me that you could adequately deal with another translator online.