Having no language, infants cannot be told what they need to learn.
Yet by the age of three they will have mastered the basic structure of their native language and will be well on their way to communicative competence.
Acquiring their language is a most impressive intellectual feat.
Students of how children learn language generally agree that the most remarkable aspect of this feat is the rapid acquisition of grammar.
What is the main subject of the passage?
How to memorize words
Language acquisition in children
Communicating with infants
Teaching languages to children
The word which in line 9 refers to
their ability
learning process
reading vocabulary
idiomatic expression