It is estimated that about 50% of the people on the planet speak at least 2 languages! We generally believe that we can’t forget our first & native language as it’s impossible. But it’s not! People can forget their mother tongue though in extreme circumstances like long-term migration & being away from your country for a long time, emotional factors like trauma & being betrayed from once country. Further, children who are removed from their country before age 12 & adults who face traumatic events can forget their first language. When we start learning second language, the two languages start competing with each other. The more familiar you become with second language, more are the chances of foreign language becoming your native language! (except people who are good at languages)! So, we CAN forget our mother language. It’s complex but not wonder!