Piaget believed that language signals the end of the sensorimotor period because this ability requires understanding a symbol stands for something else. True, in order to master language, you must grasp the idea that the abstract word-symbol textbook refers to what you are reading now. But the miracle of language is that we string together words in novel, understandable ways. What causes us to master this feat, and how does language evolve?

The essential property of language is elasticity. How can I come up with this new sentence, and why can you understand its meaning, although you have never seen it before? Why does every language have a grammar, with nouns, verbs, and rules for organizing words into sentences? According to linguist Noam Chomsky, the reason is that humans are biologically programmed to make “language,” via what he labeled the language acquisition device (LAD).

Chomsky developed his nature-oriented concept of a uniquely human LAD in reaction to the behaviorist B. F. Skinner’s nurture-oriented proposition that we learn to speak through being reinforced for producing specific words (for instance, Skinner argued that we learn to say “I want cookie” by being rewarded for producing those sounds by getting that treat). This pronouncement was another example of the traditional behaviorist principle that “all actions are driven by reinforcement” run amok (see Chapter 1). It defies common sense to suggest that we can generate billions of new sentences by having people reinforce us for every word!

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Still, Skinner is correct in one respect. I speak English instead of Mandarin Chinese because I grew up in New York City, not Beijing. So the way our genetic program for making language gets expressed depends on our environment. Once again, nature plus nurture work together to explain every activity of life!

Currently, developmentalists adopt a social-interactionist perspective on this core skill. They focus on the motivations that propel language (Hoff-Ginsberg, 1997). Babies are passionate to communicate. Adults are passionate to help babies learn to talk. How does the infant passion to communicate evolve?

The pathway to producing language occurs in stages. Out of the reflexive crying of the newborn period comes cooing (oooh sounds) at about month 4. At around month 6, delightful vocal circular reactions called babbling emerge. Babbles are alternating consonant and vowel sounds, such as “da da da,” that infants playfully repeat with variations of intonation and pitch.

The first word emerges out of the babble at around 11 months, although that exact landmark is difficult to define. There is little more reinforcing to paternal pride than when your 8-month-old genius repeats your name. But when does “da da da” really refer to Dad? In the first, holophrase stage of true speech, one word, accompanied by gestures says it all. When your son says “ja” and points to the kitchen, you know he wants juice . . . or was it a jelly sandwich, or was he referring to his sister Jane?

Children accumulate their first 50 or so words, centering on the important items in their world (people, toys, and food), slowly (Nelson, 1974). Then, typically between ages 1 1/2 and 2, there is a vocabulary explosion as the child begins to combine words. Because children pare communication down to its essentials, just like an old-style telegram (“Me juice”; “Mommy, no”), this first word-combining stage is called telegraphic speech. Table 3.10 summarizes these language landmarks, along with offering examples and the approximate time each milestone occurs.

Just as with the other infant achievements described in this chapter, developmentalists are passionate to trace language to its roots. It turns out, for instance, that newborns are prewired to gravitate to the sounds of living things—as they suck longer when reinforced by hearing monkey and/or human vocalizations (versus pure tones). By 3 months of age, preferences get more selective. Now babies perk up only when they hear human speech (Vouloumanos and others, 2010). By 8 months of age (notice the similarity to the visual-system atrophy research described early in this chapter), infants—like adults—lose their ability to hear sound tones in languages not their own, such as Hindi (Gervain & Mehler, 2010). Simultaneously, a remarkable sharpening occurs. When language starts to explode, toddlers can hear the difference between similar sounds like “bih” and “dih” and link them to objects after just hearing this connection once!

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Caregivers promote these achievements by continually talking to babies. Around the world, they train infants in language by using infant-directed speech.

Infant-directed speech (IDS) (what you and I call baby talk) uses simple words, exaggerated tones, elongated vowels, and has a higher pitch than we use in speaking to adults (Hoff-Ginsberg, 1997). Although IDS sounds ridiculous (“Mooommy taaaaking baaaaby ooooout!” “Moommy looooves baaaaby!”), infants perk up when they hear this conversational style (Santesso, Schmidt, & Trainor, 2007). So we naturally use infant-directed speech with babies, just as we are compelled to pick up and rock a child when she cries. Does IDS really help promote emerging language? The answer is yes.

Babies identify individual words better when they are uttered in exaggerated IDS tones (Thiessen, Hill, & Saffran, 2005). When adults are learning a new language, they also benefit from the slow, repetitive IDS style. Therefore, rather than being just for babies, IDS is a strategy that teaches language across the board (Ratner, 2013). In fact, notice that when you are teaching a person any new skill (or, as you will see in Chapter 14, when talking to an older person you perceive as impaired,) you, too, are apt to automatically use IDS!

The close link between brain development at 7 months of age and children’s speech understanding at age 1, shown in Figure 3.9, suggests that we can physically “see” the roots of language before that talent appears (Deniz Can, Richards, and Kuhl, 2013; see also Dean and others, 2014). But even if this growth rate is mainly genetically programmed (meaning due to biological differences), parents who use more IDS communications have babies who speak at a younger age (Ratner, 2013).

IDS is different than other talk. You don’t hear this speech style on TV, at the dinner table, or on videos designed to produce Einstein’s at 8 months of age. IDS kicks in only when we communicate with babies one on one. So, if parents are passionate to accelerate language, investing millions in learning tools seems a distant second best to spending time talking to a child (Ratner, 2013)!

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A basic message of this chapter is that—from language, to face perception, to social cognition—our main agenda is to connect with the human world. The next chapter focuses on this number-one infant (and adult) agenda by exploring attachment relationships during our first two years of life.

Question 3.18

The idea that we learn language by getting reinforced reflects Skinner’s operant conditioning perspective; Chomsky hypothesized that we are biologically programmed to acquire language; the social-interactionist perspective emphasizes the fact that babies and adults have a passion to communicate.

Question 3.19

Baby Ginny is cooing; baby Jamal is babbling; baby Sam is speaking in holophrases (one-word stage); and baby David is using telegraphic speech.

Question 3.20

No, your friend is wrong!!! Baby talk—or in developmental science terms, infant-directed speech (IDS)—helps promote early language.