Do you think it make learning English harder, easier or have no effect?

From birth. I know families that only speak their native language at home but use english when out in public.

I would say at age 6 depending on if the child was raised around mandarin Chinese speaking people.

I believe if the parents both speak different languages one could speak to the child in that language as early as soon it begins to speak. A child is flexible inasmuch as learning is concerned. The worst case scenario would be the child might code switch and speak a combination of both languages, however this in time is easily corrected.

gatita_63109

earlier the exposure the better. start at least at age 4. it has no bad effect on learning English or any other languages. do you know the world famous commodity investor Jim Rogers? (I think he's in top the 10 list of richest man in the world) He hired a chinese nanny for his daughter and asked her to communicate with her only in mandarin.