As a child grows, he's able to associate new meanings with new ideas and objects. Language development occurs with normal socialization. Children---particularly 4-year-olds---will mimic their parents' and other caregivers' speech patterns.
By the time a child is 4, he should be able to identify familiar animals and common objects that he sees, according to the Child Development Institute. He will tend to repeat the same phrases, syllables and sounds often. Children who are 4 should know at least four colors and body parts; they should also ask questions often.
Four-year-olds also enjoy dramatic, imaginative play. They will often play make-believe and should use extensive verbalization as they carry out activities.
Expect a four-year-old to begin speaking in the past tense and to use contractions when appropriate.
A 4-year-old child can usually speak in more complex sentences; interact with him using this type of language on a regular basis. While you're doing day-to-day tasks, tell him in a more complex way what you're doing. The National Network for Child Care says to watch for your four-year-old to adapt to another speaker's speech pattern; this is a normal part of language development. Expect the child to answer who, what, when, where and why questions and be able to follow two unrelated instructions, such as "Go put the scissors away, and then get your milk."
Gently help your child develop his language skills by working on the correct pronunciation of words and basic grammar skills. For instance, if your child says, "I hurted my knee," instead of correcting her, simply reply, "Oh, you hurt your knee?"
Help your child learn to classify objects. For instance, instruct him to tell you what types of food he eats and what types of items keep him warm when it's cold outside.
Because 4-year-olds are often eager to communicate, they might start to stutter. If this happens, allow the child time to think and answer; don't interrupt. Show the child that you're patient and can wait for him to answer.
Also, don't expect perfection in his speech patterns.