I suppose I can speak both American and Queen’s English, though I grew up with the latter (my dad is from England).
I learned starting at 3 years old 😊
Now, I am onto a third language of Galician, which is spoken in my country. Maybe I will even learn a fourth for my Japanese girlfriend but her close/immediate family all speaks English.
When I was 10, I moved to another country and started studying in an international school. I essentially only spoke Portuguese (my mother tongue) with my parents and my brother, which meant I was fully immersed in English for a huge chunk of my formative years.
English isn’t technically my mother tongue, but it might as well be. I write better in English than I do in Portuguese, because that’s the language I wrote in in school. My Portuguese is flawless, and nobody would ever say that is isn’t my mother tongue, but in some situations my English is just better. I consider myself to have two mother tongues, even though I’m technically an ESL speaker.
I have also not been able to replicate my level of English in other languages. I’m fluent in German, and I have no difficulty with any aspect of the language, be it reading, speaking, writing or listening, but it’s really clear that it is not my mother tongue.
English is basically like my mother tongue too! I learn at age 3!