I'm bi-lingual (English/Cantonese). What's that got to do with it? Well, came across this article (via Reuters) Switching languages can also switch personality: study. It's mainly about study on people who switch betweem English and Spanish, and studying their behaviour.
"Language can be a cue that activates different culture-specific frames," the researchers said in a study published in the Journal of Consumer Research.
I definitely can relate to that, take for instance, how I behave when I talk to my Irish friends and my Chinese friends when we all go out. My tone completely changes when I speak Cantonese, I'm more closer to Hong Kongers type of speaking here. I find that I am more expressive when I speak in Cantonese. I haven't thought how I really feel when I speak in English, I'm probably more serious?!? I think this would be quite hard off the top of my head unless I take notes all the time on my behaviour when I speak in either languages. Maybe someone might feel different who speaks more than one language.