[chryuop]

Actually in Italy we tend to speak bad Italian ourselves when we speak to a foreigner. If their Italian is very bad we tend to lower to their level of errors because we think they understand better.

As a non native living abroad let me tell you that I appreciate if my wife corrects me (native speaker) when I make big errors. But had she corrected me every mistake I did, I would have stopped talking to her a long time ago. Sorry, but it gets old after a while.
I used to exchange email with penpals in Japan and we both corrected every single mistake in every email...the exchange didn't last long, because the emails were getting heavy and tiring.
Now they let my errors slip and I let theirs slip too, correcting only the major ones and communication is much more enjoyable. I agree that school is for perfecting grammar....