If you speak fluently two languages that means you are bilingual. Speaking the second language brings a lot of benefits and makes some of your cognitive functions more developed than those at monolingual people. For example, you probably have a better attention span and can multitask better. Among the murmurs or in a noisy room you are most likely to be the one being able to distinguish speech. Also, because of the cultural and social opportunities, it is very probable that you are open-minded (unless you are closed-minded by conviction, then it doesn't really matter which and how many languages you speak). The truth is that:
You can never understand one language until you understand at least two. G. Willans
Also, if you are one of the lucky polyglots there is a chance that you are an immigrant by choice or by force, and that your original mother tongue is struggling with space inside your head.
I don't know if I can be considered trilingual but, apart from my mother tongue I have working proficiency in the other two languages. I think and write in English, with my family and childhood friends I speak Serbian, Croatian, Montenegrin and Macedonian (which can be considered as one language but the political climate in Balkans needed this strict distinction among otherwise completely mutually interchangeable languages). All my daily conversations and chit-chats are spoken in Portuguese, news I receive is communicated in Portuguese and most of my new relationships are built in this language.
Sometimes I wonder if my Serbian friends suddenly learned Portuguese would we have the same conversations as we do now; if I spoke English with my parents would we have completely different topics, would my mother still be telling dirty jokes we all know but still laugh until belly ache… And if I could speak Serbian at work, would I sound more mature. I wonder if I am a different person when I speak different languages, but I guess I already know the answer to that.
There is this strange sensation that I have different age depending on the language I speak as they too need time to mature within us. In Serbian, I am fully equipped grown-up person, in English, I am getting serious but not too much and in Portuguese, I am still just a playful teenager.
Speaking many languages can be a struggle, but I love the possibility to express myself in three languages, to discover new words for feelings I didn't know I felt and the sweet pain of sharing emotions that only have a name in one of the languages. In my head these three perfectly blend, I can easily write my notes in all three combined (and understand it), my thoughts do the same but when I need to focus on only one I miss the words from the others and I feel incomplete. How it's possible that having more can make you feel like you are less.
It is strange that every time I go back to Serbian it feels like entering the room where I still need to learn its proportions, as for some time I feel like standing in the middle of it but not being able to understand its size and how far are the walls. I feel dizzy and foolish that it takes seconds to recall names of the things that just a few years ago I didn't even know how it sounded in other languages. But Serbian is coming from my soul, from the essence of who I am and it is easy to reconnect, it takes just a familiar smell or voice to switch inside me and turn me into loud Balkan girl, fully proficient.
English comes from my head, it is the rational part of me — part of my academic life and almost all of my professional life happened in English, it is the cold reason.
With Portuguese it's different. I never took classes of Portuguese, I learned it by speaking… and sometimes I surprise myself by the phrases I say out loud and wonder where did that come from. Because Portuguese, this Latin, romantic language speaks to my heart and when I talk Portuguese it's like breathing, and the less I think about what I want to say and how it sounds, the more articulated and harmonious it becomes. I fell in love with the language and I learned it by eating delicious food, by drinking the most amazing wine and kissing with strangers (two kisses in the cheek is how Portuguese people greet everyone, in case of doubt). Portuguese comes from the heart.
So, you see language can define territory or a group of people but it comes from a place within us.