Language development goes through a critical stage between the ages of two and four.
This is according to research in the Journal of Neuroscience, which has discovered environmental factors play a big part in a toddler's development, BBC News reports.
UK and US scientists collaborated on the project, as 108 children between the ages of one and six with normal brain function were studied.
Brain scans were used to look at the level of myelin - the insulation that develops from birth - present in the brain.
The researchers discovered the distribution of this dielectric is fixed from the age of four, which is why youngsters are better equipped to learn more than one language.
Dr Jonathan O'Muircheartaigh from King's College London led the study and he said: "Since our work seems to indicate that brain circuits associated with language are more flexible ... early intervention for children with delayed language attainment should be initiated before this critical age."
Posted by Harriet McGowan