Frankly, a question I’ve never asked myself before!
Speaking more than one language myself and as an expat, thus being immersed in another culture, speaking a foreign language on a daily basis, I never really had a doubt to act as another person than I am, whether here in France or in my home country.
But, that’s one thing research is good for, asking questions independent of the (sometimes predictable or at least rather unsurprising) outcome.
So, I read this article in Psychology Today with interest.
I guess, there is little doubt that if you are a bilingual or possibly multilingual yourself, you will know about the feeling to behave differently or also speak differently in your second or third language compared with your speech in your native language.
Well, to make it short and sweet, this is simply our human way to adapt or to shift depending on the context or culture we find ourselves in at that moment. This might result in someone speaking faster in Spanish or using more gestures in Italian whereas he or she would be considered more business-like speaking English. Still, no conflict of personality. We simply switch and adapt. And yes, a native Spanish speaker will still most-likely be able to identify the U.S. American in you. Maybe, he or she will compliment you on your Spanish which, following the underlying message of the article, might well be interpreted as you being well-immersed in the cultural aspects of the language, going beyond pure language skills.
That said, the author introduces the reader to the interesting difference between mono-cultural bilinguals who make the majority of bilinguals and bi-cultural bilinguals, people who grew up in two cultures. The latter may be seen as acting differently depending on the situation, so yes using their other personality if you will. This is of course the consequence of being perfectly familiar with their two cultures, so knowing exactly how to behave in a particular situation. As they are perfectly immersed in both cultures, it might appear as two personalities although it isn’t. In a sense, we could say these people are just better adapted than us who learnt other languages later in life and connected learnt about different cultures only then as well.
That said, you might be interested to hear that our ability to speak foreign languages can help us make better decisions and this is not connected to the time when we learnt these. Mono-cultural bilinguals might even have the edge over bi-cultural bilinguals in that aspect!
Picture by Chicago National Prtg. & Engr. Co.Modifications by Papa Lima Whiskey, via Wikimedia Commons