The following excerpts are from an article in the Translation Guy blog:

In a recent study by psychologists at Hong Kong Polytechnic University, researchers discovered that bilingual Chinese English speakers have a split personality, at least when they are speaking English and Chinese. “[Native] Chinese students who were fluent in English appeared more assertive and aggressive and open to new experiences,” which are the kinds of personality traits often associated with blue-eyed foreigners in a Chinese cultural context.

In Scientific American, writer Nathan Collins reports that the personality effects of language also varied depending on whether the interviewer was a Westerner or Chinese, even when both used English. “Personalities are not fixed. Instead the language a person is speaking—and with whom―can lead individuals to take on the personality traits of the culture associated with the language or the person.”

In my own bicultural household, I get grief from my wife for the way I act in Japanese. Seems I come off too fake, plus I speak Japanese like a girl. Apparently my NYC “Fuck you and have a nice day” persona plays better for her, but come to think of it she complains about the way I act in English too. Fuggedaboutit. Read more.

See: Translation Guy Blog