According to noam chomsky, the fact that children all over the world acquire language at the same time indicates that

It indicates that nature must furnish youngsters with a biological, prewired, universal grammar, enabling them to comprehend the essential rules of all dialects and to apply these guidelines to speech they hear.
Noam Chomsky presented the theory that the LAD represent the quick speed at which kids appear to learn dialect and its rules. Later advanced into Chomsky's more prominent hypothesis of universal grammar.