As in Opera 12.18, when text is selected on a web page, right-click and open the Translate submenu to translate the text to any other supported language.
I have edited my context menu to reduce the list to those languages I am likely to use. In Vivaldi I use a Web Panel for this, but a context menu would be more convenient. My Web Panel is OK for translating other languages to English. To translate in the other direction takes a lot more clicks.
This opens a new tab with the text translated to the chosen language. Translation engines would also provide some income for Vivaldi.