12.7: Language Development

Do newborns communicate? Absolutely! However, they do not communicate through language. Instead, they communicate their thoughts and needs with body posture (being relaxed or still), gestures, cries, and facial expressions. A person who spends adequate time with an infant can learn to distinguish between cries that indicate pain and those that indicate hunger, discomfort, or frustration, as well as interpret their vocalizations, movements, gestures, and facial expressions.

Figure \(\PageIndex{1}\): An infant looking up at the camera. Image by Heather Carter is licensed CC BY-NC-ND 4.0.

Theories of Language Development

How do babies and toddlers learn to understand and use language? Researchers have different ideas about how this process happens. Some believe language is something we’re born ready to learn, while others think it develops through interaction and experience. A few key theories help explain how young children acquire language: Noam Chomsky’s idea of the Language Acquisition Device (LAD), the nativist perspective, interactionism, and statistical learning.

Chomsky and the Language Acquisition Device

Linguist Noam Chomsky (1957, 1965) argued that humans are naturally wired to learn language. He suggested that babies are born with a Language Acquisition Device (LAD)—an innate mental system that helps them acquire grammar and structure without needing explicit instruction. This helps explain why children can put sentences together in new ways they’ve never heard before. Even with limited exposure to language, children appear to absorb its rules and patterns quickly.

Figure \(\PageIndex{2}\). Noam Chomsky (1977). Image is licensed CC0 1.0.

Nativism

Chomsky’s theory is part of a larger concept known as nativism, which posits that the ability to learn language is largely innate to the brain (Pinker, 1994). Evidence for this comes from research on critical periods—specific windows of time when learning language is easiest (Lenneberg, 1967). For example, children who aren’t exposed to language early in life may struggle to develop their language skills fully later on. Nativists believe that while experience is important, the brain is already set up to acquire language from birth.

Interactionism

While nativists focus on what is already in the brain, interactionist theories highlight the role of social interactions in language learning. This perspective suggests that babies learn language by engaging with the people around them—listening to speech, responding to gestures, and participating in conversations (Vygotsky, 1978; Bruner, 1983). Caregivers play a significant role by engaging with children, asking questions, and encouraging their responses. Research shows that children raised in language-rich environments tend to develop stronger vocabulary and communication skills (Hoff, 2006).

Statistical Learning

Another way infants and toddlers learn language is through statistical learning, or picking up patterns in the speech they hear. Even before they understand words, infants can track which sounds frequently occur together and use that to figure out word boundaries (Saffran et al., 1996). This means that while children may be naturally prepared to learn language, they also rely heavily on experience and exposure to spoken words. Statistical learning helps explain how babies absorb a great deal of language information without formal instruction. This is similar to the 'predict-a-text' feature on a phone. If you were to start typing a text to a friend, your phone would auto-generate words as soon as you type in a letter based on common words starting with that letter, as well as words you use frequently that start with the letter. This is a type of statistical learning for the AI that powers many devices.

Language and the Brain

Two key areas in the brain work together to support language: Broca’s area, located in the left frontal lobe, and Wernicke’s area, found in the left temporal lobe. Broca’s area is responsible for speech production and grammatical structure (Broca, 1861), while Wernicke’s area is essential for language comprehension (Wernicke, 1874).

When infants begin recognizing familiar words, Wernicke’s area processes their meaning. As toddlers start forming sentences, Broca’s area helps them structure speech correctly. The two areas communicate through the arcuate fasciculus, a bundle of nerve fibers that allows for smooth back-and-forth processing between understanding and speaking.

Figure \(\PageIndex{3}\). Broca's and Wernicke's areas are connected via the arcuate fasciculus. Image is licensed CC BY 3.0.

Damage to Broca’s area can result in Broca’s aphasia, where a person struggles to form complete sentences but still understands speech. In contrast, damage to Wernicke’s area can cause Wernicke’s aphasia, where speech remains fluent but lacks meaningful content. This distinction highlights the specialized roles these areas play in language learning and use.

During infancy and toddlerhood, the brain rapidly strengthens these language connections, allowing children to go from recognizing words to forming meaningful sentences. Understanding how these regions develop provides insight into early language acquisition and potential delays.

Aspects of Language

Language development in early childhood is a complex process that involves mastering five key aspects: phonology, morphology, syntax, semantics, and pragmatics. These components work together to help young children acquire and use language effectively.

1. Phonology refers to the sound system of a language, including the rules for combining sounds. In early childhood, infants begin by recognizing speech sounds (phonemes) and gradually learn to produce them. Babbling transitions into recognizable words as children refine their articulation and develop phonemic awareness, a skill essential for later reading development (Kuhl, 2004).
2. Morphology is the study of word formation and structure, including prefixes, suffixes, and root words. As toddlers expand their vocabulary, they begin applying morphological rules, such as adding "-s" to form plurals or "-ed" to indicate the past tense. Overgeneralization errors, like "goed" instead of "went," reflect their active learning of these rules (Berko, 1958).
3. Syntax involves the rules governing sentence structure and word order. Young children gradually learn to form grammatically correct sentences, progressing from simple two-word phrases ("want cookie") to more complex sentences by age three. This syntactic development is influenced by caregiver interactions and the amount of language exposure in the child’s environment (Hirsh-Pasek & Golinkoff, 1996).
4. Semantics refers to the meaning of words and phrases, as well as the structure of sentences. Vocabulary growth is a critical milestone in early childhood, as children learn to connect words with concepts. The rapid increase in vocabulary, known as the "vocabulary explosion," typically occurs between 18 and 24 months (Bloom, 2000). A child's ability to understand and use words meaningfully supports their later literacy and cognitive development.
5. Pragmatics is the social aspect of language, involving conversational rules, turn-taking, and understanding nonverbal cues. Toddlers and preschoolers refine these skills through social interactions, learning how to adjust their speech based on context and audience. Pragmatic development is crucial for effective communication and social competence (Tomasello, 2003).

Stages of Language Development

Prenatal Foundations

Language development begins before birth as the fetus becomes attuned to the sounds of its environment. Around the third trimester, the auditory system is developed enough for the baby to hear and respond to external sounds, particularly the mother's voice and the rhythmic patterns of speech (DeCasper & Fifer, 1980). Research indicates that newborns recognize and prefer the language spoken by their mother during pregnancy, suggesting that they engage in early auditory learning (Kuhl, 2004). Additionally, fetuses can detect prosody—the melody and rhythm of speech, which helps lay the groundwork for distinguishing different speech sounds after birth. This early exposure to language sounds primes infants for later language learning, making the prenatal period a crucial stage in the foundations of communication.

Stage 1: Preverbal Communication

Infants begin to vocalize and repeat vocalizations within the first couple of months of life. That gurgling, musical vocalization, called cooing, can serve as a source of entertainment for an infant who has been laid down for a nap or seated in a carrier on a car ride. Coos serve as practice for vocalization, as the infant hears the sound of their voice and tries to repeat sounds that are entertaining. Infants also begin to learn the pace and pauses of conversation as they alternate their vocalizations with those of someone else and then take their turn again when the other person’s vocalization has stopped. Cooing initially involves making vowel sounds, such as “oooo”. Later, consonants are added to vocalizations such as “nananananana”.

Stage 2: Babbling and Gesturing

At about four to six months of age, infants begin making even more elaborate vocalizations that include the sounds required for any language. Guttural sounds, clicks, consonants, and vowel sounds are ready to equip the child with the ability to repeat the sounds characteristic of the language being heard. Eventually, these sounds will no longer be used as the infant grows more accustomed to a particular language. Deaf babies also use gestures to communicate wants, reactions, and feelings. Because gesturing seems to be easier than vocalization for some toddlers, sign language is sometimes taught to enhance their ability to communicate by leveraging the ease of gesturing. The rhythm and pattern of language are used when deaf babies sign, just as it is when hearing babies babble.

Figure \(\PageIndex{4}\). Infants' first sounds are in the form of babbling, accompanied by gestures such as hand movements and various facial expressions. Image by Heather Carter is licensed CC BY-NC-ND 4.0.

At around ten months of age, the infant can understand more than he or she can say. You may have experienced this phenomenon as well if you have ever tried to learn a second language. You may have been able to follow a conversation more easily than contribute to it.

Stage 3: First Words (Holophrastic)

Children typically begin using their first words at around 12 or 13 months of age and may use partial words to convey their thoughts at even younger ages. These one-word expressions are referred to as holophrastic speech. For example, the child may say “ju” for the word “juice” and use this sound when referring to a bottle of juice. The listener must interpret the meaning of the holophrase, and when this is someone who has spent time with the child, interpretation is not too difficult. They know that “ju” means “juice” which means the baby wants some milk! But someone who has not been around the child will have trouble understanding what is meant. Imagine the parent who, to a friend, exclaims, “Ezra’s talking all the time now!” The friend hears only “ju da ga,” which, the parent explains, means “I want some milk when I go with Daddy.”

First words, if the child is using English, tend to be nouns. The child labels objects such as a cup or a ball. In a verb-friendly language such as Chinese, however, children may learn more verbs. This may also be due to the varying emphasis placed on objects based on cultural context. Chinese children may be taught to notice the action and relationship between objects, while children from the United States may be taught to name an object and its qualities (such as color, texture, and size). These differences are evident when comparing the interpretations of art by older students from China and the United States.

Figure \(\PageIndex{5}\): Two children playing with toys. Image by the U.S. Air Force is in the public domai n.

A child who learns that a word represents an object may initially think that the word can be used only for that particular object. Only the family’s Irish Setter is a “doggie”. This is referred to as underextension. More often, however, a child may think that a label applies to all objects that are similar to the original object. In overextension, all animals become “doggies”, for example.

Stage 4: Two-Word (Telegraphic)

One-year-olds typically have a vocabulary of about 50 words. But by the time they become toddlers, they have a vocabulary of about 200 words and begin putting those words together in telegraphic speech (I think of it now as 'text message' speech because texting is more common and is similar in that text messages typically only include the minimal amount of words to convey the message).

Words are soon combined, and 18-month-old toddlers can express themselves further by using expressions such as “baby bye-bye” or “doggie pretty”. Words needed to convey messages are used, but the articles and other parts of speech necessary for grammatical correctness are not yet used. These expressions sound like a telegraph (or perhaps a better analogy today would be that they read like a text message) where unnecessary words are not used. “Give baby ball” is used rather than “Give the baby the ball.” Or a text message of “Send money now!” rather than “Dear Mother, I really need some money to take care of my expenses.”⁹

Figure \(\PageIndex{6}\): A toddler playing with a toy telephone. Image by Salim Virji is licensed under CC BY-SA 2.0.

Child-Directed Speech

Why is a horse a “horsie”? Have you ever wondered why adults tend to use “baby talk” or that sing-song type of intonation and exaggeration used when talking to children? This represents a universal tendency and is known as child-directed speech, also referred to as parentese (historically known as motherese). It involves exaggerating the vowel and consonant sounds, using a high-pitched voice, and delivering the phrase with great facial expression. Why is this done? It may be in order to clearly articulate the sounds of a word so that the child can hear the sounds involved. Or it may be because when this type of speech is used, the infant pays more attention to the speaker, and this sets up a pattern of interaction in which the speaker and listener are in tune with one another. ¹²

References, Contributors and Attributions

9. Children’s Development by Ana R. Leon is licensed under CC BY 4.0

12. Children’s Development by Ana R. Leon is licensed under CC BY 4.0

13. Children’s Development by Ana R. Leon is licensed under CC BY 4.0

Berko, J. (1958). The child's learning of English morphology. Word, 14(2-3), 150–177. https://doi.org/10.1080/00437956.1958.11659661

Bloom, P. (2000). How children learn the meanings of words. MIT Press.

Broca, P. (1861). Remarks on the seat of the faculty of articulated language, followed by an observation of aphemia. Bulletin de la Société Anatomique, 6, 330–357.

Bruner, J. (1983). Child’s talk: Learning to use language. Oxford University Press.

Chomsky, N. (1957). Syntactic structures. Mouton.

Chomsky, N. (1965). Aspects of the theory of syntax. MIT Press.

DeCasper, A. J., & Fifer, W. P. (1980). Of human bonding: Newborns prefer their mothers’ voices. Science, 208(4448), 1174-1176.

Hirsh-Pasek, K., & Golinkoff, R. M. (1996). The origins of grammar: Evidence from early language comprehension. MIT Press.

Hoff, E. (2006). How social contexts support and shape language development. Developmental Review, 26(1), 55–88. https://doi.org/10.1016/j.dr.2005.11.002

Kuhl, P. K. (2004). Early language acquisition: Cracking the speech code. Nature Reviews Neuroscience, 5(11), 831–843. https://doi.org/10.1038/nrn1533

Lenneberg, E. H. (1967). Biological foundations of language. Wiley.

Pinker, S. (1994). The language instinct: How the mind creates language. HarperCollins.

Saffran, J. R., Aslin, R. N., & Newport, E. L. (1996). Statistical learning by 8-month-old infants. Science, 274(5294), 1926–1928. https://doi.org/10.1126/science.274.5294.1926

Tomasello, M. (2003). Constructing a language: A usage-based theory of language acquisition. Harvard University Press.

Vygotsky, L. S. (1978). Mind in society: The development of higher psychological processes. Harvard University Press.

Wernicke, C. (1874). The symptom complex of aphasia: A psychological study on an anatomical basis. Cohn & Weigert.