It depends on the meaning of 'you'. If you're talking about a general point of view, we use the impersonal form. Example: When you speak about having fun, Australia is the answer; (Quando si parla di divertimento, l'australia è la risposta. but we also accept the form: Quando parli di divertimento...) If you're talking about a precise point of you, the "normal form" is correct . Example: When you speak to them, I fall asleep (Quando parli con loro, io mi addormento)

Thank you for the answers. Simone, good tip :-)

I forgot it: Don't rely on google translator :)

In this case the particle "si" is reflexive try to read something here: http://www.locuta.com/Si.html