A couple of Automator workflows to translate the selected text with Google Translate.
The Google Translate workflow can receive any text: just right click on the
selected text and chose "Google Translate" from the "Services" contextual
menu.
A few applications, like macOS's Preview, won't allow to do that, though.
The Google Translate Selection workflow works around that by copying the
selected text to the clipboard and translating from there. It has to be called
from the application's menu (instead of the contextual menu).
Just double click the .workflow files. You can add keyboard shortcuts by
going to the keyboard preferences, selecting "Shortcuts" and then "Services".
Most of the credits go to this guy: https://medium.com/@mrdoro/fast-translation-with-google-translator-and-mac-osx-817e32233b7a