Why is it easier for kids to learn languages than it is for adults?

ST. PAUL, Minn. — Many of us wish we could learn another language. It seems young kids have no problem picking up a second or third language but for adults, that changes. 
At the Star of the North School in St. Paul, English is off-limits.
Kindergarten is a key age at the school — one of three French immersion schools in the state.
“We encourage you to start when you are little,” Principal Sofia Bossard said. “It’s always the younger the better.”
Why is it easier for kids to learn languages than it is for adults?
“If you look at the research it’s the plasticity of the brain, which is the scientific explanation, and the risk-taking, which is the psychological factor. So little kids are able to take risks and their brain has not gotten in the practice of doing the same thing over and over again,” Bossard said.
Bossard, who is from Bulgaria and speaks three languages, confirms there is another perk from early learning: once you learn one language, it’s easier to learn the rest.
“Once you are immersed in a language setting, you can take on more languages easily because the brain knows what to do,” she said.
And more languages mean more laughs.
“My sister goes to this school too, in second grade, so we can always just talk to each other at the dinner table and my parents are gonna be like, ‘What?'” one student said.
Bossard says the good news is that it’s never too late to learn a new language, but it will take some humility. She says you will need to start at the kindergarten level, though it’s faster if you can travel and immerse yourself