Drag this bookmarlet to your bookmark bar.

Once installed, click on this bookmarklet in your bookmark bar to activate it. A popup will appear at the top left of your page. Click and drag it to where you need. Select the language to translate from and to. Then select the word on the page you'd like translated. Repeat as necessary.

Currently, this bookmarklet only really works on Rai News. Maybe one of these days I'll get around to making it work anywhere.