As one hits puberty it is not unusual to delve deeper into who you are as a person and discovering your identity. I have found this phase in life to be extra tricky growing up bilingual.
I grew up in a bilingual home, speaking both Dutch and English. As a teenager, I started to realise I had developed two quite different personalities in both languages. In Dutch, the language I spoke all day long, I have a very outgoing personality. However, in English, which I only spoke at home, I tend to be more reserved, quiet, and serious. As a linguistics student I can now partially explain why this shift in identity takes place with bilingual children/ teenagers.
Last year, I managed to conduct a small survey to research the experiences of other bilingual students concerning their identity. In this survey participants pointed out two common causes.
The first one being that the cultural context connected to the language plays an imminent role in how one expresses oneself in that language. For example: Italians are stereotypically known to gesticulate a lot while talking.
Therefore, a bilingual child might develop a more expressive personality in Italian than in their other mother tongue. Secondly, did not only the cultural context play a role but also the context in which the child learned the language such as, with whom or where they learnt the language.
Lastly, I would like to state that this subject is still fairly untouched by researchers, and everyone experiences language learning and the identities that develop along with that process differently.