Critical period hypothesis is somewhat debated in linguistics. Children and Adults just learn differently. Children have far less inhibitions and more time. The

Critical period hypothesis is somewhat debated in linguistics. Children and Adults just learn differently. Children have far less inhibitions and more time. The second part of your comment sounds like pseudoscience. I learned German in my late 20s and speak to native speakers every day, where I live bilingual is the norm and a whole lot of people acquire second, third or forth languages as adults.