Dilemma over the language!

I understand your point. However, I don't think babies or little children need to learn too many languages. From the age of 5 or 6, one can possibly imagine that one parent could start speaking in another language as a kind a private lesson. Actually, the best in this case is to enroll the child in a bilingual school, or a school that uses another language than the one of the country in which they live. For example, living in Japan with a Japanese parent and the other native English speaker, they would speak only Japanese and English (e.g. the mother speaks only Japanese to the child and the father only English), then from age 5, the child would join a French school and have lessons mostly in French (and maybe a bit of Japanese ?). I know a French guy who was raised in Japan in a normal Japanese school and whose parents spoke only French and English to him. He was already perfectly bilingual French-Japanese and could speak English very fluently as a teenager, while all his Japanese friends spoke only Japanese. That's another good way of become polyglot early. Another solution would be to move country and thus have the child study in different languages (and cultures !) every few years. It's a bit harder as the child would have to adapt to a new environment and culture every time, which is psychologically demanding for children. I's a good solution for late teenagers and university students to study a few years abroad in another language. That's a great experience