If you partially forget your first language, is it still your first language, or your mother tongue, or what? Could you relearn it to a standard that it became your first language again?
I lived in Spain until I was 3 before moving to England and until I was 4-5 I spoke English as a second language (my mum's English and my dad's Spanish). My dad has always spoken to me in Spanish but naturally not being immersed in the language, my spanish deteriorated and now I speak English wayyy more fluently than spanish, but I want my language and my culture back! If I went back to live in Spain later on in life, could I relearn Spanish as my first language?
...or just paranoid?