The infant learns that actions cause consistent effects. Language Development Delays in language development are more common than delays in other developmental domains. Receptive language skills reflect the ability to understand language. Expressive language skills reflect the ability to make thoughts, ideas, and desires known to others. Receptive language is characterized by an increasing ability to localize sounds, such as a bell.
Expressive language consists of cooing.
At about 3 months, the infant will begin vocalizing after hearing an adult speak. In so doing, parents reinforce the repeated use of these sounds. The infant's realizes that people have names and objects have labels. By 12 months of age, some infants understand as many as 100 words. They can follow a simple command as long as the speaker uses a gesture.