I know this because I was also kind of ashamed. You just grow up speaking English and learning in English. At home you speak Spanish to your family and the Spanish is never quite as good as theirs and no where near as good as a person who has an education in Spanish (most folks who come to the US from Latin America are from small rural areas with low opportunities) so when you grow up in USA you’re teased at school for speaking Spanish and teased from native Spanish speakers that you don’t speak it right. It also has to do that our brains are firing two languages since we’re kids. So when I can’t find a word in English when I’m Spanish or vice versa I fill it with the other language. This works mostly with other kids who are growing up the same as you. For example sometimes you have brain farts and in elementary school you’re reading out loud and have the temptation to read in English word in Spanish and people laugh because they think you’re dumb. Of course people like me have to educate the young kids that you can obtain a college education in English while pursuing to better your English but most will just let the English over take them. Personally, i think most Hispanics who were born and raised here won’t do this because they don’t educate themselves enough to know their history and why it’s so beneficial and helpful to speak both languages. I hope this helps. If you have any other questions message me because I think the bottom part of my opinion is not popular with a lot of Hispanics.