This question is for my class and I'm trying to find more answers
Babies hear the sound and watch the movement. A new neuron (nerve cell) is formed with each new sound. Eventually these neurons are activated with the same sound and they see the same movement. That forms a connection of sound and movement and the language is developed. Now they hear a different sound but the same movement. A connecting neuron makes them differentiate the meaning of two different sounds with same movement and learning of language is initiated.
Hope this helps.