Phonological development

Learning to talk is a huge journey for a child. It begins with learning how to organize sounds into meaning. This process is called phonological development. To understand language, children must learn to separate a stream of speech into units. When we speak, there are no spaces between our words. An infant might hear "thisisacup" as one long sound. They must learn to segment that stream into "this," "is," "a," and "cup." Once they find a word like "cup," they can give it a meaning. They must also learn that "cup" is different from "cub."

Children learn to hear sounds long before they can say them. At one month old, infants can tell some speech sounds apart. For example, they can hear the difference between /b/ and /p/. Researchers like Eimas et al. (1971) studied this by watching how much infants sucked. They found that babies pay more attention to sound changes near a category boundary. By four months, infants prefer the way adults talk to babies. They start to track the pitch and rhythm of speech. By six months, they use statistical learning to find patterns. They listen to how often certain sounds occur in their language.

Making sounds is another important part of growing up. This starts with reflexive vocalizations like crying or sneezing. Between six and sixteen weeks, babies make happy cooing sounds. From sixteen to thirty weeks, they enter a stage of vocal play. They combine vowel and consonant sounds into longer sequences. At six months, babies often start reduplicated babbling. This is when they repeat the same sounds, like "bababa." Around ten months, they move to nonreduplicated babbling. They mix different vowels and consonants together. They might even use "protowords," which are made-up words for specific things.

There are many interesting facts about how this works. At five months, babies often prefer hearing their own names. By seven and a half months, English-learning infants use "prosodic bootstrapping." This means they use the rhythm of words to find where they start and end. At nine months, they learn which sound combinations are possible in their language. By twelve months, most children say their first real word. Their ability to understand words grows faster than their ability to speak them. A ten-month-old might know between 11 and 154 words.

This development connects how we hear to how we speak. Perceptual abilities, or how we hear, usually come before production, or how we speak. As children grow, their brains tune themselves to their native language. Infants can hear many different sounds from all over the world. However, by twelve months, they focus on the sounds used by people around them. This tuning helps them become experts in their own language. Even after they start talking, their skills keep growing. Some parts of how we hear speech do not fully develop until age twelve.