I don't think that's right - it looks like the stat is that 78% of Americans speak *only* English at home.

I'm not American, but anecdotally, a supermajority (like 80-90%) of people I know who speak multiple languages at home speak English at native fluency. (e.g. in my semi-extended family - parents/siblings/nibblings/partner/parents-in-law, there are 9 of us, and only 2 are more comfortable in French than English, but none of us would qualify as speaking *only* English at home.)

Also, look into how the statistic is gathered vs other countries.

There is no exact definition on this statistic and how to measure. There is also reporting biases. Single person vs household for example.

I don't care what language they read, just that they're capable of reading (and thinking) like adults.