Pointing Toward Two-Word Speech in Young Children

The first two-word combinations that a child produces are significant for two reasons. First, they reflect the child’s developing ability to express propositional information within a single communicative act. Rather than produce and in separate utterances, the child can now conjoin them within a single sentence, baby drink , thus explicitly signaling that there is a relationship between the two elements. Second, two-word baby drink combinations are the child’s first step into syntax. Independent of the language they are learning, children across the globe tend to produce the words that comprise their sentences in a consistent order. The particular orders they use mirror the orders provided by the language models they experience— rather than baby drink for an English-learning child. Even when the language a child is learning has relatively free word drink baby order, the child tends to adhere to a consistent pattern based on a frequently occurring adult pattern. These two features of early two-word combinations are robust. They are found in the first two-sign combinations produced by deaf children acquiring a conventional sign language from their deaf parents (Newport & Meier, 1985), and even in the first two-gesture combinations invented by deaf children not yet exposed to conventional sign language by their hearing parents (Goldin-Meadow, 1997, 2002a). Children begin to produce two-word sentences at approximately 18 months of age. They have, however, been able to produce isolated words since 12 months. Why is there a delay between the onset of words and the onset of word combinations? Combining two words into a single communicative act requires a number of skills. Children not only need to be able to intend to convey a proposition; they must also be able to segment that proposition into elements, label those elements with words, and combine the words into a single string. Until children actually produce two words in a single combination, there is no explicit evidence in their talk that they intend to convey a proposition. There is, however, evidence that children in the one-word period can produce two elements of a proposition in one communicative act—but only if one looks across modalities. One-word children can utter a word— — and indicate the object of that action through their drink gestures—a point at a bottle. Assuming that gesture and speech are functioning as a unit, the two modalities together convey, to the observant listener, two elements of a single proposition. In this chapter, we explore whether combinations in which gesture and speech convey different but complementary information are a transitional bridge between oneand two-word speech. We require two lines of evidence to support this hypothesis. First, in order for this type of combination to be a stepping-stone, gesture and speech must be functioning as a unified system. We therefore begin by exploring the onset of this type of combination in relation to the moment when gesture and speech come together into a well-integrated system—an event that takes place sometime during the oneword period (Butcher & Goldin-Meadow, 2000). Next, we ask if integrated gesture-speech combinations are a harbinger of two-word combinations. Specifically, we explore the onset of combinations in which gesture and speech convey different information in relation to the onset of two-word speech. Whether these gesture–speech combinations precede or co-occur with two-word speech can provide insight into the conditions needed to combine words within a single sentence. If all that is needed for two-word combinations is the cognitive ability to convey two elements within a single communicative act, then gesture–speech combinations of this sort ought to co-occur with, and not precede with any regularity, the onset of two-word speech. Alternatively, if additional languagespecific skills are required for the onset of two-word combinations, then gesture–speech combinations in which the two modalities convey different information might be expected to reliably precede the onset of two-word speech. Our goal here is to situate the onset of combinations in which gesture and speech convey different Co py ri gh t @ 20 03 . Ps yc ho lo gy P re ss .