Firefox: SelectionSK is a Firefox extension that offers language translations, highlighting and multi-engine search to highlighted text on any page. Simply highlight the text you want to search for and select the engine you want to use, make it stand out, copy it in plain text, or email the text to a friend.
Open the SelectionSK preferences and you can toggle which entries appear in the menu. You can copy and append the selection to the clipboard, copy the highlighted text as plain text, or add "Translate" and "Translate With" buttons to change the text into your native language.
The developer doesn't have a similar extension for Chrome, but you can try Selection Search to get the same multi-engine search in the right-click menu. Chrome translates text on the fly and already allows you to view "selection source" natively. Still, if you switch browsers or prefer Firefox, SelectionSK is worth a try.