Human Interaction is Crucial to Language Learning
Babies are born with the innate ability to reproduce sounds in all languages, but at the age of 6 months they begin to discard those not needed to decode and reproduce their own language.
By the time they have reached 12 months, they are no longer able to distinguish the nuances of sounds not relevant to their native tongue.
Interaction with Native Speakers Helps
However, a study of 9- to 10-month old infants by the University of Washington’s Dr. Patricia Kuhl showed that infants and toddlers who played with and were read to by native speakers of a foreign language were able to keep the window open for foreign language acquisition.
An unexpected finding was that the foreign language exposure via TV or audio tapes did not result in learning with this age group.