Yeah, language is a non-issue for me. Children learn language when they’re young. We pick up vocabulary through absorption and no one really analyzes what they’re saying or writing when speaking in their natural tongue.
We can try to teach people second languages later in life, be it immigrants or our own native students learning a second language in high school, but it ends up being broken and survivalist. Our high school students don’t graduate fluent in Spanish and French, and we don’t really expect them to even though we force them to take the classes.
To speak a language WELL, you need to learn it before age 8 OR spent a LOOOOT of time in the culture where it dominates. I have immigrant relatives that can run their own business, but even 30 years into living in America, you can tell their language isn’t anywhere as good as a native. Their kids of course, speak Hollywood-accent English like anyone else who grew up on TV in America.
^^Then again, that suggests Schwarzenegger is right, because the kids of the immigrants need to absorb English. This will primarily be from TV if they hear Spanish spoken in their house. If a kid is introduced to multiple languages early in life, there is no harm in that and they can be truly fluent in both without much conscious effort.