In my experience, learning a second language to a high level involves some amount of disassociation. Only people I know without this experience spoke both languages from a very early age usually at home. So this tracks.
But there can be other factors as well. For example in social contexts can change sharply between languages. The way I talk with my family is very different from the way I speak professionally—at home I'm the youngest and at work I'm the boss.
But there can be other factors as well. For example in social contexts can change sharply between languages. The way I talk with my family is very different from the way I speak professionally—at home I'm the youngest and at work I'm the boss.