For expat parents, passing on their native languages can be a struggle.Not sharing your first language with loved ones is hard.Not passing it on to your own child can be especially tough.Many expat and immigrant parents feel a sense of failure; they wring their hands and share stories on par-enting forums and social media, hoping to find the secret to nurturing bilingual children successfully. 

Children are linguistic sponges, but this doesn't mean that cursory exposure is enough.They must hear a language quite a bit to understand it and use it of ten to be able to speak it comfortably.This is mental work, and a child who doesn't have a motive to speak a language—either a need or a strong desire—will often avoid it.Children's brains are already busy enough.So languages of tenwither and die when parents move abroad.That's because, typically, the first generation born in America is bilingual, and the second is monolingual—in English, the children often struggling to speak easily with their immigrant grandparents. 

In the past, governments discouraged immigrant families from keeping their languages.These days, offcials tend to be less interventionist, some even see a valuable resource in immigrants' lan-guage abilities.Yet many factors conspire to ensure that children still lose their parents' languages,or never learn them.A big one is institutional pressure.A child's time spent with a second language is time not spent on their first.So teachers often discourage parents from speaking their languages to their children.(This is especially true if the second language lacks prestige.)Parents oft en reluctantly comply, worried about their offspring's education.This is a shame; children really can master two languages or even more.Research does indeed suggest their vocabulary in each language may be somewhat smaller for a while.But other studies hint at cognitive advantages among bilinguals.They may be more adept at complex tasks, better at maintaining attention, and (at the other end of life)suffer the onset of dementia later. 

Even without those side-effects, though, a bilingual child's connection to relatives and another culture is a good thing in itself.How to bring it about? When both parents share the heritage lan-guage, the strategy is oft en to speak that at home, and the national language outside.But when they have different languages, perhaps the most common approach is “one parent, one language”.Fran-cois Grosjean, a linguist at the University of Neuchatel in Switzerland, emphasises necessity.He re-commends reserving occasions on which the only language that may be spoken is the one that needs support.Sabine Little, a German linguist at the University of Sheffield, puts the emphasis elsewhere.Making the heritage language yet another task imposed by parents can lead to rejection, she argues.She recommends letting the child forge their own emotional connection to the language.Ms Little suggests learning through apps and entertainment made for native speakers; the educational type smack of homework, she thinks.