Both of my little brothers were born here in the US to Spanish parents. my mother speaks Spanish to them whereas my stepdad speaks to them in English. they hear English in school and I talk to them in both. so why is it hard for them to speak and understand Spanish? I understand and am fluent in Spanish so I don’t have the same issues, however, I’m not sure if my different upbringing has something to do with it. I was born in DR where everyone spoke Spanish, I was there till I was 3 years old, moved to the US and in school was taught English, my mother still spoke to me at home in Spanish as well as other family members, but I only heard English outside of the home. I now speak and understand both languages perfectly, so why is it different for my brothers? is it because from a young age they heard both instead of one? this topic is both psychological and linguistic. you just need to find articles that relate to this, and write about them. I will write in the storytelling part. Need 5 peer-reviewed articles.