Phonological development

Babies learn how to talk.

It starts before they are born. They listen to sounds in the womb.

First, babies make small noises. They cry or sneeze. Later, they make happy cooing sounds.

These sounds help them practice.

Babies also listen very closely. They learn which sounds belong to their home language. They can even hear their own name!

Next, they try babbling. They might say "ba-ba-ba." This helps them learn to use their mouths. They use different sounds to make words.

Soon, they say their first word. This usually happens around one year old. Learning to talk is a big job!

How do babies learn to talk? It is a big job. It starts even before they are born. Babies listen to sounds while in the womb.

First, babies learn to hear. At one month old, they can tell speech sounds apart. They can even hear the difference between sounds like /b/ and /p/. By five months, babies like to hear their own names. By six months, they use math in their heads. They listen to how often sounds occur. This is called statistical learning. It helps them find patterns in speech.

Next, babies practice making sounds. At first, they make reflexive sounds like crying or sneezing.

Later, they make happy cooing sounds. Between six and ten months, they try reduplicated babbling. This is when they repeat sounds like "ba-ba-ba." Soon, they try nonreduplicated babbling. They mix different sounds together. They might even make "protowords." These are made-up words used for specific things. Around one year old, they say their first real word.

Learning to speak takes many years. It is not finished until the teenage years.

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.

Phonological development is the process by which children learn to organize sounds into meaningful language. This journey begins with phonology, which is the study of how sounds function within a language. To master speech, a child must first learn to distinguish different sounds. They must also learn to segment the continuous speech stream they hear into individual units. In spoken language, there are no spaces between words like there are in printed text. An infant might hear the sequence "thisisacup" and must learn to divide it into "this," "is," "a," and "cup." Once a sound unit like "cup" is extracted, the child assigns it a meaning. They must also learn to distinguish "cup" from "cub" to understand they are different words.

Perceptual abilities, or the ability to hear and categorize sounds, usually develop before production, which is the ability to speak. This development begins in the womb and continues until the teenage years. At just one month old, infants show categorical perception. This means they perceive certain speech sounds as belonging to specific categories. For example, the sounds /b/ and /p/ differ by the amount of breathiness following the opening of the lips. In a 1971 study, Eimas et al. used a computer-generated continuum of breathiness to test English-learning infants. They monitored the infant's sucking rate to measure their attention. They found infants paid more attention to differences near the boundary between /b/ and /p/ than to differences within a single category.

As infants grow, they refine how they track suprasegmental information. This refers to the pitch, rhythm, and stress patterns of speech. At four months, infants prefer infant-directed speech over adult-directed speech. They can even recognize these preferences when only the pitch contours are played. By five months, babies often prefer hearing their own names. By six months, infants use statistical learning to process their ambient language. They notice how often certain sounds occur. If a language has a bimodal distribution, where sounds occur mostly at the extreme ends of a continuum, infants learn to discriminate them better. They also learn to ignore sound variations that are not meaningful, such as different voices speaking the same vowel.

At six months, infants use prosodic features to help them segment speech. This process is called "prosodic bootstrapping." They use the stress patterns of their language to find word boundaries. In English, which often uses a strong-weak or "trochaic" stress pattern, seven-month-old infants can segment words using this rhythm. However, they struggle to segment words that follow a weak-strong pattern. By nine months, infants understand phonotactics. This is the rule for which combinations of sounds are possible in their native language. By twelve months, the perceptual system has been tuned to the specific contrasts of the native language.

Speech production follows a specific sequence of developmental stages. The first stage, from birth to six weeks, involves reflexive vocalizations. These include crying and vegetative sounds like breathing or sneezing. These sounds help infants familiarize themselves with their vocal apparatus. From six to sixteen weeks, infants enter the cooing and laughter stage. Cooing is often triggered by social interaction and sounds similar to vowels. Between sixteen and thirty weeks, infants engage in vocal play. They combine vowel and consonant-like sounds into longer sequences. During this time, they produce vowels first, followed by back consonants like [g] and [k] around two to three months. Front consonants like [m], [n], and [p] appear around six months.

Between six and ten months, children enter the stage of reduplicated or canonical babbling. This involves repeating consonant-vowel syllables, such as "bababa." At this stage, babbling begins to show "babbling drift," where the sounds are influenced by the language the infant hears. For example, nine-month-old French-learning infants produce more prevoiced stops than English-learning infants. From ten to fourteen months, infants move to nonreduplicated or variegated babbling. They combine different vowels and consonants into complex syllable strings. They may also use "protowords," which are invented words used consistently for specific meanings. Around twelve to fourteen months, children typically produce their first real words.

Understanding language and speaking it develop at different rates. Comprehension vocabulary, the words a child understands, usually grows faster than production vocabulary. At ten to eleven months, a child's comprehension may range from 11 to 154 words, even if they cannot speak yet. By sixteen months, comprehension can range from 92 to 321 words, while production is typically around 50 words. At fourteen months, children can distinguish between different "words" if they sound very different, like "lif" and "neem." However, they struggle with similar-sounding words like "bih" and "dih" because the cognitive load of learning meaning makes phonological distinction harder.