As usual, the perpetually "know better than the rest of you" NYT gets it wrong. The article states:
"Researchers, educators and policy makers long considered a second language to be an interference, cognitively speaking, that hindered a child’s academic and intellectual development." BS.
In fact, it has had broad acceptance since the 1940s that languages learned before puberty expand cognitive function that lasts a lifetime. Not so good after puberty, but still worthwhile. I learned six after puberty. My grandson learned three before, and at 14 is working on his fifth.
Languages learned before puberty get the added benefit of being accent free and put into the mother's language locus of the brain. Also, the more languages learned before puberty, the more complex is the development of the facial, throat and tongue neuromuscular systems, and one can therefore learn additional languages with less accent — but word retrieval is associative rather than direct.
Whether ideology or science, the NYT, like the BBC, ceased being the "anything of record" sometime in the 70s.