Closed-class words or function words are limited in number and act as guides for sentence structure. The use of closed-class words makes your child’s sentences easier to understand.
For example, as your child’s language skills develop he will use the prepositions in and on. He will understand the preposition under. He will also use gestures to tell the meaning of locational prepositions (such as pointing).
Prepositions like on, in, under are easier for your child to understand than behind, beside, and between. Have you ever asked your child to bring you a ball? You give clues such as “It is in front of the door.” Even with this clue, he still has difficulty locating the ball. This is because your child has to identify the relationship between the front and the back of an object (a ball has no identifiable parts). Therefore, for your child to use a preposition correctly, he must first understand its meaning. This skill develops beyond the age of three.
Phonology
Phonology is how speech/word sounds are used and organized in your child’s language as he learns to talk. This area of development is a cognitive skill, and it is a strong predictor of future academic success. Your child was not born being able to make all the word choices and patterns of language. He goes through this developmental process because he is learning to coordinate his tongue, lips, teeth, etc. Think back to the time when you heard your child say something such as “baba” for bottle. Even now, if your child just turned three, you may hear him say “nail” for “snail.” As your child continues to develop, he will stop using incorrect speech sounds and articulate and enunciate increasingly complex sentences.
