So what happens when you learn a second, or third, or fourth language fluently? [Like, say me?]
Do you suddenly have multiple-personalities?
Complete bollocks.
So does your 'identity' (whatever that is) change half way through the sentence. In you head?
Are you literally a different person at either end of your sentence?
SMH.
Thanks for your sophisticated analysis.[1]
Psycho-activeness of language has an incredible depth of account from philosophy to semiotics. But a simple enough paper I found for you that exemplifies (not exhaustively proves) my claim is Holtgraves & Kashima, 2008. It is freely accessible.
Additionally equivocating personality, identity and pathologies like dissociative personality is going to mislead us, because they are strawman arguments.
Think of yourself growing up. Turning to an adult was a change in identity. Do you remember the day you switched from being a child to being an adult? Was it a psychopathology to become an adult? Are you completely dissociated from childhood memories, and seemingly, your childhood ego-states?
Finally I will pull another comment of yours in this thread;
> No here is the thing: none of this has affected my identify at all, not even in the slightest.
The thing with identity is that it is not entirely transparent to us. You don't know who you are as much as you think you do. Not only that, if language is the ground on which our identities form, by definition you wouldn't realize a change in identity due to change in grounding. By these accounts you wouldn't be the most reliable witness to assess your identity change.
[1] I know sarcasm is frowned up in this forum but I wanted to give an example of how we use language to emotionally regulate ourselves. We can sublimate our anger by creating a contradictory perspective to salience the unfairness of the opposing perspective. It gives us a strategy out of merely attacking back in kind. Collect thousands of tools like this together and you bet it significantly contributes to your identity.
Neither then would anyone else, including the OP.
Learning new languages does add different layers to your personality.
I am native-level fluent in three languages, and have some level of fluency in three more.
Learning a new language opens a complete new door to a new culture, and way of thoughts through books, movies, songs, and so much more.
Even if you don't spend time to learn a culture well, i.e. don't listen to music or read literature, learning a new grammar, and very importantly, new words, do reshape you, and gives you new perspectives and ways of thoughts.
Some of these a polysynthetic languages, others are agglutinative. Two are tonal, and one doesn't have an alphabet.
No here is the thing: none of this has affected my identify at all, not even in the slightest. Same person: just different sounds for things.
Presumably my testimony counts as well.