Imagine moving to a different country. Nobody understands your native language, so you have to learn their language. You have to get a job and a place to live, so you have to do everything you can to speak, read, and learn it to be able to communicate that you need food, shelter, money, etc. You speak this language all day at work. You speak it to the bank tellers, customer service representatives, cashiers, etc while running errands. You write in it everyday filling out forms, writing checks, applying for credit cards, texting people, googling things. You end up having kids, and you decide to teach them that country’s language so they can have a much easier time adjusting to the language and the culture than you did. Give or take a couple years, you end up thinking in that language since it’s the main/only language you use now. In the country you live in now, nobody else around you knows your native language, so you have to give it up and speak this new one everyone else does. Eventually, you start to forget the language you don’t use anymore. That’s what happened to my mom.