At the preschool age, your little Shakespeare is probably already stunningly good at making affirmative, declarative sentences. In other words, she is apt to spout out statements that she believes are true, though you may disagree on factuality of the content. Anyway, don’t fill yourself up on your child’s factual statements. The preschool years are when your child begins to supply you with new sentence form sweetness.
When parents hear from developmental psychologists that children learn to use negatives at the preschool age, most moms smile and proudly exclaim, “My child can already use negatives!” While this may be true for even very young children, during preschool is when children learn to use negation correctly. Prior to preschool, most children add negation to their sentences with a simple “no” or “not” in the beginning or end of a sentence. More advance speakers may even place these words in front of a verb, but still incorrectly. For example, a child who has not developed proper negation use might say, “I no wear shoe.” During preschool, children learn how to use auxiliaries; in short, this means you will hear your angel throw tantrums more eloquently, with “No, I didn’t,” “You don’t like me,” and other such beautiful phrases.
Again, most mothers proudly state that their children could ask good questions prior to preschool. For example, to many moms, “I sit chair” is a question--it's not the content, but the way my child says it! With a rising intonation on the end, these declarative sentences become questions. This works for communication between mother and child, but is not a grammatically-correct sentence. In preschool, children begin to use auxiliaries, making their questions clearly questions. Preschoolers’ yes/no questions start with words such as “does” and “will.” And at this time, children begin to break out of the yes/no question phase, bravely venturing into asking "wh-" questions, beginning with “who,” “what” and “where.” In most preschoolers, the “wh” phase comes before the correct versions of yes/no questions.
Late in the preschool phase, your child will begin to use a sentence form rare even in many adults: the passive form. From 3- to 5-years-old, your child will begin to intersperse his speech with sentences that make the object more important than the subject. This means your child is becoming much more aware of social concepts and what separates inanimate objects from socially important objects. So, when your child comes inside telling you that his “scissors can be putten in the pocket” you should be both proud--your child is using passive sentences--and concerned--scissors do not belong in your child’s pockets. Even later, your child will develop a sense of using passive sentences to express negative events, such as when “my friend was punished.”
So your child isn’t exactly a Shakespeare yet, but by the end of her preschool years she will be using a variety of complex sentences--sentences with several clauses. You will likely first notice these in commands, when your child demands you watch her do something. A sentence like “watch me draw you” is complex in that it contains two verbs. From here, your child will begin to add “wh-“ words into sentences, not meaning for them to be questions, as in “I show you when we get home.” From this point onward, you will begin to hear conjunctions such as “or” and “if” in little Shakespeare’s sentences. And from there, the sky is the limit--or maybe even a best-selling book.