Quite a while ago I made a shirt which had 请讲普通话 (“Please speak (standard) Mandarin”) on the front, and started selling it on the Sinosplice store (through CafePress). The idea is that if you challenge the people around you to talk to you in Chinese, they probably will. It wasn’t until my last visit to the States in February that I was able to pick up my own “Please speak Mandarin” t-shirt, and not until the weather warmed up recently that I was actually able to see the effect.
The first time I used it was in a cafe, where the waiter insisted on talking to me in English, even though I initiated in Chinese. It was a classic language power struggle. I pointed to my shirt and asked him to 请讲普通话, which was incredibly awkward for me to do. He then got it, but clearly found it extremely difficult to not use English with a foreigner.
Later in the day, I caught several girls reading my shirt, laughing, and pointing it out to their friends. They didn’t talk to me.
So, it’s only been Day 1 of the experiment, but so far empirical evidence suggests that this shirt may be amusing to Chinese girls. (My wife, on the other hand, found it a little embarrassing.)
Related: Other Sinosplice original t-shirts