Quick Translate - it’s application for quick translate text using Google Translate.
How to use:
1. Click application icon in status bar and choose "Open Translate Window" from menu. You can set global hot key for this action.
2. Enter text and press "Translate" button or press ⌘+↩.
Or
1. Select text in any applications and choose "Quick Translate" from context menu.
Also Quick Translate have support of Apple Script.
Tricks:
Use ⌘+Z for toggle original/translated text.
Click on label with translate direction for quick toggle it or press ⌘+S.