Also, some words are quite difficult or almost impossible to translate into other languages.

> mix words from each language into a sentence without realizing it

I still do that today. I'll just be talking casually and be like... wait, what did I just say? haha.

optimism

My brother (at around 7), on the other hand, struggled a lot with it and would mix words from each language into a sentence without realizing it.

At some point, his teacher asked my parents to agree on using one language at home and reserve the use of others (and then only those exclusively) to specific events or locations.

They never managed to uphold the discipline required for that, so we stuck to one language from there on out.

AskSN

Has anyone ever felt disconnected from where you were born and grew up?

Natalia

Not all kids can do that though.

I was trilingual by the age of 10. 
My brother (at around 7), on the other hand, struggled a lot with it and would mix words from each language into a sentence without realizing it.

At some point, his teacher asked my parents to agree on using one language at home and reserve the use of others (and then only those exclusively) to specific events or locations.
They never managed to uphold the discipline required for that, so we stuck to one language from there on out.