Language: What Develops in the First Two Years?

The brains of no other species have anything approaching the neurons and networks that support the 6,000 or so human languages. Many other animals communicate, but the human linguistic ability at age 2 far surpasses that of full-grown adults from every other species. How do babies do it?

The Universal Sequence

The sequence of language development is the same worldwide (see At About This Time). Some children learn several languages, some only one, some learn rapidly and others slowly, but they all follow the same path. Even deaf infants who become able to hear (thanks to cochlear implants) follow the sequence, catching up to their age-mates unless they have multiple disabilities (Fazzi et al., 2011). Those who learn sign language also begin with one word at a time, and then sign sentences of increasing length and complexity.

Who Is Babbling? Probably both the 6-month-old and the 27-year-old. During every day of infancy, mothers and babies communicate with noises, movements (notice the hands), and expressions.

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Language learning begins before birth (Dirix et al., 2009). Newborns prefer to listen to the language their mother spoke when they were in the womb, not because they understand the words, of course, but because they are familiar with the rhythm, the sounds, and the cadence.

Surprisingly, newborns of bilingual mothers differentiate between both languages (Heinlein et al., 2010). Data were collected on 94 newborns (0 to 5 days old) in a large hospital in Vancouver, Canada. Half were born to mothers who spoke both English and Tagalog (the native language of Filipinos), one-third to mothers who spoke only English, and one-sixth to mothers who spoke English and Chinese. The bilingual mothers used English in more formal contexts and non-English with family.

The infants in all three groups sucked as they listened to 10 minutes of recorded sentences in English or Tagalog matched for pitch, duration, and number of syllables. Most of them with bilingual mothers preferred Tagalog, whereas those with monolingual mothers preferred English. The Chinese bilingual babies (who had never heard Tagalog) nonetheless preferred it. The researchers believe that they liked Tagalog because the rhythm of that Asian language is more similar to Chinese than to English (Heinlein et al., 2010).

Young infants attend to voices more than to mechanical sounds (a clock ticking) and look closely at the facial expressions of someone talking to them (Minagawa-Kawai et al., 2011). By 6 months, simply by seeing someone’s mouth movements (no sound), infants can distinguish whether or not that person is speaking their native language (Weikum et al., 2007). By 1 year, even when they don’t understand the actual content of the speech, they are more likely to imitate the actions of a stranger speaking their native language than those of a person who speaks another language (Buttelmann et al., 2013).

Infants’ ability to distinguish sounds in the language they hear improves, whereas the ability to hear sounds never spoken in their native language (such as how an “r” or an “l” is pronounced) deteriorates (Narayan et al., 2010). If parents want a child to speak two languages, they must speak both of them to their infant.

In every language, adults use higher pitch, simple words, repetition, varied speed, and exaggerated emotional tone when talking to infants (Bryant & Barrett, 2007). This special language form is sometimes called baby talk, since it is directed to babies, and sometimes called motherese, since mothers universally speak it. Non-mothers speak it as well. For that reason, scientists prefer the more formal designation, child-directed speech.

No matter what term is used, child-directed speech fosters learning, and babies communicate as best they can. By 4 months, they squeal, growl, gurgle, grunt, croon, and yell, telling everyone what is on their minds in response to both their own internal state and their caregivers’ words. At 7 months, infants begin to recognize words that are highly distinctive (Singh, 2008): Bottle, dog, and mama, for instance, might be differentiated, but words that sound alike (baby, Bobbie, and Barbie) are not.

Show Me Where Pointing is one of the earliest forms of communication, emerging at about 10 months. As you see here, pointing is useful lifelong for humans.

IMAGE SOURCE/GETTY IMAGES

Not only do infants prefer child-directed speech, but they also like alliteration, rhymes, repetition, rhythm, and varied pitch (Hayes & Slater, 2008; Schön et al., 2008). Think of your favorite lullaby (itself an alliterative word); obviously, babies prefer sounds over content.

Between 6 and 9 months, babies repeat certain syllables (ma-ma-ma, da-da-da, ba-ba-ba), a vocalization called babbling because of the way it sounds. Babbling is experience-expectant; all babies babble, even deaf ones. Since babies like to “make interesting sights last,” babbling increases in response to child-directed speech. Deaf babies stop babbling but increasingly engage in responsive gesturing.

Toward the end of the first year, babbling begins to sound like the infant’s native language; infants imitate accents, cadence, consonants, and so on. Videotapes of deaf infants whose parents sign to them show that 10-month-olds use about a dozen distinct hand gestures in a repetitive manner similar to babbling.

Many caregivers, recognizing the power of gestures, teach “baby signs” to their 6- to 12-month-olds, who communicate with hand signs months before they can master moving their tongues, lips, and jaws to make specific words. There is no evidence that baby signing accelerates talking (as had been claimed), but it does seem to make mothers more responsive, which itself is an advantage (Kirk et al., 2013).

One early gesture is pointing, an advanced social gesture that requires understanding another person’s perspective. Most animals cannot interpret pointing; most 10-month-old humans look toward wherever someone else points and can already use a tiny index finger (not just a full hand) to point themselves, even to a place where an object belongs but is not yet there (Liszkowski et al., 2009; Liszkowski & Tomasello, 2011). Pointing is well developed by 12 months, especially when the person who is pointing also speaks (e.g., “look at that”) (Daum et al., 2013).

First Words

Finally, at about 1 year, the average baby utters a few words, understood by caregivers if not by strangers. For example, at 13 months, a child named Kyle knew standard words such as mama, but he also knew da, ba, tam, opma, and daes, which his parents knew to be, respectively, “downstairs,” “bottle,” “tummy,” “oatmeal,” and “starfish.” He also had a special sound that he used to call squirrels (Lewis et al., 1999).

In the first months of the second year, spoken vocabulary increases gradually (perhaps one new word a week). However, meanings are learned rapidly; babies understand about 10 times more words than they can say. Initially, the first words are merely labels for familiar things (mama and dada are common), but early words are soon accompanied by gestures, facial expressions, and nuances of tone, loudness, and cadence (Saxton, 2010). Imagine meaningful communication in “Dada,” “Dada?” and “Dada!” Each is a holophrase, a single word that expresses an entire thought.

Intonation (variation in tone and pitch) is extensive in both babbling and holophrases, but it is temporarily reduced at about 12 months. Apparently, at that point infants reorganize their vocalization from universal to language-specific (Snow, 2006). They are no longer just making noises; they are trying to communicate in a specific language. Uttering meaningful words takes all their attention—none is left over for intonation.

Careful tracing of early language finds other times when vocalization slows before a burst of new talking begins; perception affects action (Pulvermüller & Fadiga, 2010). Thus neurological advances may temporarily inhibit vocalization (Parladé & Iverson, 2011).

Spoken vocabulary builds rapidly once the first 50 words are mastered, with 21-month-olds typically saying twice as many words as 18-month-olds (Adamson & Bakeman, 2006). This language spurt is called the naming explosion because many early words are nouns, that is, names of persons, places, or things.

Between 12 and 18 months almost every infant learns the name of each significant caregiver (often dada, mama, nana, papa, baba, tata) and sibling (and sometimes each pet). (See Appendix A.) Other frequently uttered words refer to the child’s favorite foods (nana can mean “banana” as well as “grandma”) and to elimination (pee-pee, wee-wee, poo-poo, ka-ka, doo-doo).

Notice that all these words have two identical syllables, each a consonant followed by a vowel sound. Many words follow that pattern—not just baba but also bobo, bebe, bubu, bibi. Other early words are only slightly more complicated—ma-me, ama, and so on. The meaning of such words varies by language, but every baby says such words, and everywhere, culture assigns meaning to them.

Cultural Differences

Cultures and families vary in how much child-directed speech children hear. Some parents read to their infants, teach them signs, and respond to every burp or fart as if it were an attempt to talk. Other parents are much less verbal. They use gestures and touch; they say “hush” and “no” instead of expanding vocabulary.

By 5-months, babies prefer adults who often use child-directed speech, even when those talkative adults are temporarily silent. Apparently, just as infants seek to master motor skills as soon as they can, they seek to learn language from the best teachers available (Schachner & Hannon, 2011). They soon favor the words, accents, and even musical rhythms of their culture (Soley & Hannon, 2010).

Cultural Values If they are typical of most families in the relatively taciturn Otavalo culture of Ecuador, these three children hear significantly less conversation than children elsewhere. In most Western cultures, that might be called neglect, a form of maltreatment. However, each culture encourages the qualities it values, and verbal fluency is not a priority in this community. In fact, people who talk more than listen are ostracized, and those who keep secrets are valued, so encouragement of child talk may be maltreatment in Otavalo.

WOLFGANG KAEHLER/CORBIS

Although all new talkers say names, use similar sounds, and prefer nouns more than other parts of speech, the ratio of nouns to verbs and adjectives varies from place to place. For example, by 18 months, the ratio of nouns to verbs is higher in English-speaking infants than Chinese or Korean infants. Why?

One explanation goes back to the language itself. Chinese and Korean are “verb-friendly” in that verbs are placed at the beginning or end of sentences. That facilitates learning. English verbs occur anywhere in a sentence, and their forms change in illogical ways (e.g., go, gone, will go, went). This irregularity makes English verbs harder to learn.

An alternative explanation considers the entire social context: Playing with a variety of toys and learning about dozens of objects are routine in North America, whereas East Asian cultures emphasize human interactions—specifically, how one person responds to another. Accordingly, North American infants are expected to name many objects, whereas Asian infants are expected to act on objects (as explained in Chapter 1) and respond to people. Thus, Chinese toddlers might learn the equivalent of come, play, love, carry, run, and so on early in life.

A simpler explanation is that young children are sensitive to sounds. Verbs are learned more easily if they sound like the action (Imai et al., 2008), and such verbs are more common in some languages than others.

English does not have many onomatopoeic verbs, which makes verb-learning difficult. (Jump, kiss, and poop—all learned early on—are exceptions.) When the same word could be a noun or a verb, English-speaking mothers say them differently: kiss, for instance, is emphasized more as a noun than a verb, so babies learn the noun before the verb (Conwell & Morgan, 2012). The infant’s focus on sounds explains why many toddlers who have never been on a farm know that cows “moo” and ducks “quack.”

Grammar includes all the methods that languages use to communicate meaning. Word order, prefixes, suffixes, intonation, verb forms, pronouns and negations, prepositions and articles—all of these are aspects of grammar. Grammar can be discerned in holophrases but it becomes obvious between 18 and 24 months, when babies begin to use two-word combinations (Bremner et al., 2010).

For example, “Baby cry” and “More juice” follow grammatical word order. No child asks, “Juice more,” and even toddlers know that “cry baby” is not the same as “baby cry.” By age 2, children combine three words. English grammar uses subject–verb–object order; for example, toddlers say “Mommy read book,” rather than any of the five other possible sequences of those three words.

Children’s grammar correlates with the length of their sentences, which is why in every language mean length of utterance (MLU) is considered an accurate way to measure a child’s language progress (e.g., Miyata et al., 2013). The child who says “Baby is crying” is advanced in language development compared with the child who says “Baby crying” or simply the holophrase “Baby.”

Young children can master two languages, not just one. Children are statisticians: They implicitly track the number of words and phrases and learn those expressed most often, in one, two, or more languages (Johnson & Tyler, 2010). [Lifespan Link: Bilingual learning is discussed in detail in Chapter 9.]

Theories of Language Learning

Worldwide, people who are not yet 2 years old already speak their native tongue. They continue to learn rapidly: Some teenagers compose lyrics or deliver orations that move thousands of their co-linguists. How is language learned so easily and so well?

Answers come from three schools of thought, each of which is connected to a theory introduced in Chapter 2: behaviorism, sociocultural theory, and evolutionary psychology. The first theory says that infants are directly taught, the second that social impulses propel infants to communicate, and the third that infants understand language because of brain advances thousands of years ago that allowed survival of our species.

The seeds of the first perspective were planted more than 50 years ago, when the dominant theory in North American psychology was behaviorism, or learning theory. The essential idea was that all learning is acquired, step-by-step, through association and reinforcement. Just as Pavlov’s dogs learned to associate sound with food, infants may associate objects with words, especially if reinforcement occurs.

B. F. Skinner (1957) noticed that spontaneous babbling is usually reinforced. Typically, every time the baby says “ma-ma-ma-ma,” a grinning mother appears, repeating the sound and showering the baby with attention, praise, and perhaps food. The baby learns affordances and repeats “ma-ma-ma-ma” when lonely or hungry; through operant conditioning, talking begins.

Skinner believed that most parents are excellent instructors, responding to their infants’ gestures and sounds, thus reinforcing speech (Saxton, 2010). Even in preliterate societies, parents use child-directed speech, responding quickly with high pitch, short sentences, stressed nouns, and simple grammar—exactly the techniques that behaviorists would recommend.

The core ideas of this theory are the following:

• Parents are expert teachers, although other caregivers help.
• Frequent repetition is instructive, especially when linked to daily life.
• Well-taught infants become well-spoken children.

Behaviorists note that some 3-year-olds converse in elaborate sentences; others just barely put one simple word with another. Such variations correlate with the amount of language each child has heard. Parents of the most verbal children teach language throughout infancy—singing, explaining, listening, responding, and reading to their children every day, even before age 1 (Forget-Dubois et al., 2009) (see Figure 6.2).

Maternal Responsiveness and Infants’ Language Acquisition Learning the first 50 words is a milestone in early language acquisition, as it predicts the arrival of the naming explosion and the multiword sentence a few weeks later. Researchers found that the 9-month-old infants of highly responsive mothers (top 10 percent) reached this milestone as early as 15 months. The infants of nonresponsive mothers (bottom 10 percent) lagged significantly behind.

Source: Adapted from Tamis-LeMonda et al., 2001, p. 761.

Same Situation, Far Apart: Before Words The Polish babies learning sign language (top) and the New York infant interpreting a smile (bottom) are all doing what babies do: trying to understand communication long before they are able to talk.

JANEK SKARZYNSKI/AFP/GETTY IMAGES
VIKRAM RAGHUVANSHI/GETTY IMAGES

The second theory is called social-pragmatic. It arises from the sociocultural reason for language: communication. According to this perspective, infants communicate because humans are social beings, dependent on one another for survival and joy. Each culture has practices that further social interaction; talking is one of those practices. Thus, all infants (and no chimpanzees) master words and grammar to join the social world in which they find themselves (Tomasello & Herrmann, 2010).

According to this perspective, it is the emotional messages of speech, not the words, that propel communication. In one study, people who had never heard English (Shuar hunter-gatherers living in isolation near the Andes Mountains) listened to tapes of North American mothers talking to their babies. The Shuar successfully distinguished speech conveying comfort, approval, attention, and prohibition, without knowing any of the words (Bryant & Barrett, 2007). This study suggests that the social content of speech is universal, and since babies are social creatures, they learn whatever specifics their culture provides.

Evidence for social learning comes from educational programs for children. Many 1-year-olds enjoy watching television and videos, but they learn from it only when adults are actively involved in teaching (see Opposing Perspectives: Language and Video, below). In a controlled experiment, 1-year-olds learned vocabulary much better when someone taught them directly than when the same person gave the same lesson on video (Roseberry et al., 2009).

A third theory holds that language learning is genetically programmed to begin at a certain age; adults need not teach it, nor is it a by-product of social interaction (theories one and two). It arises from the universal human impulse to i mitate. As already explained in the research on memory, infants and toddlers observe what they see and they apply it—not slavishly but according to their own concepts and intentions, which develop as the brain matures. Theory three proposes that this is exactly what they do with the language they hear (Saxton, 2010).

This perspective began soon after Skinner proposed his theory of verbal learning. Noam Chomsky (1968, 1980) and his followers felt that language is too complex to be mastered merely through step-by-step conditioning. Although behaviorists focus on variations among children in vocabulary size, Chomsky focused on similarities in language acquisition—the universals, not the differences.

Noting that all young children master basic grammar according to a schedule, Chomsky cited this universal grammar as evidence that humans are born with a mental structure that prepares them to seek some elements of human language. For example, everywhere a raised tone indicates a question.

Chomsky labeled this hypothesized mental structure the language acquisition device (LAD). The LAD enables children, as their brains develop, to derive the rules of grammar quickly and effectively from the speech they hear every day, regardless of whether their native language is English, Thai, or Urdu.

Other scholars agree with Chomsky that all infants seek to use their minds to understand and speak whatever language they hear. They are eager learners, and language may be considered one more aspect of neurological maturation (Wagner & Lakusta, 2009). This idea does not strip languages and cultures of their differences in sounds, grammar, and almost everything else, but the basic idea is that “language is a window on human nature, exposing deep and universal features of our thoughts and feelings” (Pinker, 2007, p. 148).

The various languages of the world are all logical, coherent, and systematic. Infants are primed to grasp the particular language they are exposed to, making caregiver speech “not a ‘trigger’ but a ‘nutrient’” (Slobin, 2001, p. 438). There is no need for a trigger, according to theory three, because words are expected by the developing brain, which quickly and efficiently connects neurons to support whichever language the infant hears. Thus, language itself is experience-expectant, although obviously the specific words are experience-dependent.

Which of these three perspectives is correct? Perhaps all of them. In one monograph that included details and results of 12 experiments, the authors presented a hybrid (which literally means “a new creature, formed by combining other living things”) of previous theories (Hollich et al., 2000). Since infants learn language to do numerous things—to indicate intention, call objects by name, put words together, talk to family members, sing to themselves, express their wishes, remember the past, and much more—some aspects of language learning may be best explained by one theory at one age and other aspects by another theory at another age.

Although originally developed to explain acquisition of first words, mostly nouns, this theory also explains learning verbs: Perceptual, social, and linguistic abilities combine to make that possible (Golinkoff & Hirsh-Pasek, 2008). Linguists seek to understand how most children acquire more than one language; it seems that many strategies help (Canagarajah & Wurr, 2011).

After intensive study, yet another group of scientists also endorsed a hybrid theory, concluding that “multiple attentional, social and linguistic cues” contribute to early language (Tsao et al., 2004, p. 1081). It makes logical and practical sense for nature to provide several paths toward language learning and for various theorists to emphasize one or another of them (Sebastián-Gallés, 2007).

It also seems that some children learn better one way, and others, another way (Goodman et al., 2008). Parents need to talk often to their infants (theory one), encourage social interaction (theory two), and appreciate the innate abilities of the child (theory three).

The idea that every theory is correct in some way seems idealistic. However, scientists working on extending and interpreting research on language acquisition arrived at a similar conclusion. They contend that language learning is neither the direct product of repeated input (behaviorism) nor the result of a specific human neurological capacity (LAD). Rather, from an evolutionary perspective, “different elements of the language apparatus may have evolved in different ways,” and thus a “piecemeal and empirical” approach is needed (Marcus & Rabagliati, 2009, p. 281). In other words, no single theory can explain how babies learn language: Humans accomplish this feat in many ways.

What conclusion can we draw from research on infant cognition? That infants are active learners of language and concepts, that they seek to experiment with objects and find ways to achieve their goals. This is the cognitive version of the biosocial developments noted in Chapter 5, that babies strive to roll over, crawl, walk, and so on as soon as they can. (See Visualizing Development, p. 177.)

Now back to Uncle Henry: My cousins loved their mother because she knew instinctively that her babies wanted to learn. When they grew up they realized, as developmentalists recognize, that caregivers in the first weeks of life—fathers as well as mothers—can be the first, and perhaps the best, teachers.

VISUALIZING DEVELOPMENT

Early Communication and Language Development

A COMMUNICATION MILESTONES: THE FIRST TWO YEARS Months Communication MIlestone 0 Reflexive communication–cries, movements, facial expressions 1 Recognizes some soundsMakes several different cries and soundsTurns toward familiar sounds 3 A range of meaningful noises–cooing, fussing, crying, laughing.Social smile well establishedLaughter beginsImitates movementsEnjoys interaction with others 6 New sounds, including squeals, growls, croons, trills, vowel soundsMeaningful gestures including showing excitement (waving arms and legs)Deaf babies express their first signsRecognizes and reacts to own nameExpresses negative feelings (with face and arms)Capable of distinguishing emotion by tone of voiceResponds to noises by making soundsUses noise to express joy and unhappinessBabbles, including both consonant and vowel sounds repeated in syllables 10 Makes simple gestures, like raising arms for “pick me up”Recognizes pointingMakes a sound (not in recognizable language) to indicate a particular thingResponds to simple requests 12 Attends to speechMore gestures, such as shaking head for “no”Babbles with inflectionNames familiar people (like “mama”, “dada”, “nana”)Uses exclamations, such as “oh-oh!”Tries to imitate wordsPoints and responds to pointingFirst spoken words that are recognizably part of the native language 18 Combines 2 words (like “Daddy bye-bye”)Slow growth of vocabulary, up to about 50 wordsLanguage use focuses on 10-30 holophrasesUses nouns and verbsUses movement, including running and throwing, to indicate emotionNaming explosion may begin; three or more words learned per dayMuch variation: Some toddlers do not yet speak 24 Combines 3 or 4 words together. Half the toddler’s utterances are two or more words long.Uses adjectives and adverbs (“blue”, “big”, “gentle”) Sings simple songs SOURCE: AMERICAN ACADEMY OF PEDIATRICS

B UNIVERSAL FIRST WORDS Across cultures, babies’ first words are remarkably similar. The words for mother and father are recognizable in almost any language. Most children will learn to name their immediate family and caregivers between the ages of 12 and 18 months. PHOTO: R. EKO BINTORO/ISTOCK/THINKSTOCK C MASTERING LANGUAGE Childrens’ use of language becomes more complex as they acquire more words and begin to master grammar and usage. A child’s utterances, or utterances, are broken down into the smallest units of language to determine their length and complexity: SOURCE: COURTESY OF MONICA KALFUR, SLPSOURCES & CREDITS LISTED ON P. SC-1