Researchers claim that the young mind has a more dynamic structure, that a 2-year-old child has twice the brain connections or synapses as an adult.
Or else they are discouraged by the fact that they are condemned to sound clumsy and less intelligent in the new language for quite a long time. Children have a smaller vocabulary and it is easy to learn enough of a second language to communicate their needs.
For the most part, science and research support this belief.
This is an approach that adults can seek to emulate. The different subsystems involved in the acquisition of a language are assumed to have differences in developmental progression and the optimal period for acquiring them. Do children learn languages faster than adults?
And most children are not self-conscious about how they sound. This study has shown that children started learning new phonotactics effectively on the first day of the experiment, while it took adults 2 days to get the same results.
One recent study examined the ability of Dutch-speaking adults and 9-year old children to rapidly recite novel word sequences, which were in accordance with the phonotactics of Dutch language. They invariably answer in flawless English.
Bilingualism in infancy: first steps in perception and comprehension.