Within the scope of this research, we will assess the number of siblings and their position in the family in terms of birth effects language development. The words that appear early in the language of siblings, around the first birthday, are often not used as symbols. The hallmark of a word used as a symbol is that it labels an open class of referents and is not merely a verbal response to a particular stimulus or a stimulus for a particular nonverbal response. The early words have a sign character. They seem to be part and parcel of certain behavioral routines and are not separable from them. They lack the freedom to disengage themselves from the contexts in which they are embedded. They are context bound. (Fernald 1994)
Behaviors such as hand waving and banging are typically elicitable only under circumstances that resemble the situation in which the responses were trained. Characteristically, children do not themselves produce the utterances to which they have learned to respond in this manner. The parent's utterances were not learned as items of knowledge but as stimuli to be responded to. The child's behavior was acquired as part of a ritual interaction in which the vocal element was part of the stimulus situation, and it cannot be isolated from that situation.
Reich has analyzed in similar terms his son's early behavioral responses to verbal stimuli. At 8 months Adam would respond to "Where's the shoes?" by crawling over to his mother's closet where her shoes were kept. The response pattern was so narrowly defined that he would bypass his mother's shoes if encountered on the way to the closet. It took him approximately two weeks to learn to respond to the question in relation to shoes in the father's closet, two more weeks to shoes on the bedroom floor, and again two weeks to shoes on the parents' feet. Reich summarizes by saying: "It appears that the very first word meanings are formed by associating a sequence of sounds with essentially everything that is perceptually and functionally salient about the objects or actions in the environment that co-occur with that word" (Rosenblith 1992).
In fact, young children may not consider either the word or its nominal referent as essential elements in the connection they have formed. Menyuk (1988) gives some examples from the work of others on this point. Thus, a 1-year-old Russian child was trained to turn his face to a portrait of Lenin when asked "Where is Lenin?" To the observer it seemed that the child learned to connect the word Lenin with the portrait. But the child continued to turn his face to the same place even after the portrait was removed, showing that for him the question became associated with the total act of head turning. The portrait proved to be incidental in this association. Similarly, on the verbal side the child may not be responding to the critical word but rather to the global pattern of the utterance. (Menyuk 1988) Menyuk gives an example of a 1-year-old French child who was trained to respond to "Ou est la fenetre?" (Where is the window?) by turning to the window. However, he continued to turn to the window even when the question was asked in German, to which he had had no exposure. Apparently, the child responded not to the individual words but to the questioning intonation produced in the appropriate context. (Menyuk 1988)
Snyder, Bates, and Bretherton (1988) contributed quantitative evidence on the incidence of context-bound word uses. Through intensive interviews with the mothers of 32 children, whose mean age was 1;1, Snyder et al. obtained information as to the words the children comprehended and produced and the contexts in which they exhibited these competencies. On the basis of this information Snyder et al. classified the uses of each word as contextually restricted or contextually flexible. Of the instances of word comprehension that could be clearly classified into these two categories, 66% were restricted. As an example of a context-restricted response, Snyder et al. cite a child who obeyed the request "Spit it out" only when the mother's hand was under his mouth. Snyder et al. also found cases in which children obeyed utterances only when spoken by the mother in a particular tone of voice.
In the first period of word use the difference between the number of words children understand and the number they produce is very large. In the Snyder et al. (1988) study the mean number of words the children understood was 45 and the mean number they produced was 11. Differences of similar magnitude were reported by other researchers as well. (Fernald 1994) This is a much larger advantage of comprehension over production than is normal for older speakers and is probably due to the child's difficulty in controlling the fine articulatory movements necessary for speech production, as well as to the greater ease of training comprehension than production.
In mature speakers the production vocabulary is a subset of the comprehension vocabulary. This is so because both in comprehension and in production mature speakers draw on a common store of word knowledge. But children functioning on the first level do not know words; they merely use them as vocal stimuli and vocal responses. There is, therefore, no reason why there should be any relation between the vocal stimuli they respond to and the vocal responses they produce. That is, the words that young children produce may differ from the words that they comprehend.
The child's initial use of words is characteristically not symbolic. Because the word is not conceived of as a symbol for a class of referents, but as part of the situation in which it occurs, there is little free, productive generalization of words. However, not all words are contextually restricted, and even those that are restricted are not totally restricted to fixed situations. There is some generalization. The researchers, for instance, generalized dog to different dogs in the summer-resort context. Wendy produced the waving and banging gestures in response to her mother's utterances spoken in the home setting. (Fernald 1994)
Would she have made the same response if the words were uttered in a different setting or by someone other than her mother, assuming one could have properly motivated her under such circumstances? We do not know the answer to this question. But Wendy did demonstrate considerable flexibility on the response side. For instance, she was able to improvise her "make bangbang" routine; when there was no spoon in front of her she used her hands. Even more innovative was her response to "make peekaboo." Her standard procedure was to cover her face with a diaper, peek out, and smile. On one testing occasion when there was no diaper in front of her, Wendy initially looked puzzled but then took hold of a bowl and went through the usual routine. (Fernald 1994)
The emergence of symbolic-linguistic intelligence in the second year constitutes a true revolution in human development. But, like other successful revolutions, the groundwork has been laid in advance. The entire course of sensorimotor development can, in fact, be viewed as aimed at getting the child ready for symbols and language. During the first 6 months of life, infants have no representational capacity; therefore, they have no way to store knowledge and little interest in acquiring it. All they remember are the residues of their sensations and actions, their sensorimotor schemes. Young infants have little voluntary control over their sensorimotor schemes. The schemes cannot be activated at will by the infant; they are evoked by internal and external stimuli. Gradually, sensorimotor schemes become capable of increasingly greater dissociation from stimulus contexts and they begin to serve as vehicles of representation. (Rosenblith 1992)
By the end of the first year there are normally clear signs that the infant has ceased being a sensorimotor creature and is becoming an information processor. Curiosity flourishes, exploratory activities become abundant, and there are the beginnings of make-believe play. Early make-believe play is only minimally symbolic, because the representational entities in the make-believe episodes are closely tied to sensorimotor action. Thus, when Suzie pretends to drink from a cup, she is not moving very far from a familiar instrumental sensorimotor scheme. The advance is in that she is using the scheme for a representational purpose. (Rosenblith 1992)
The first manifestations of symbolic language also appear around the first birthday. During the first year, infants showed a great deal of interest in speech sounds, but the interest was focused on the pleasure inherent in hearing the sounds themselves. Now they begin to use speech referentially; they begin to make connections between sounds and meanings. But early words are limited symbolically; they are context bound. Gradually, children achieve an appreciation, in the second half of the second year, for the social-symbolic character of word meaning, and when this happens their vocabularies increase by leaps and bounds.
Productive syntax begins about a month or two after the vocabulary growth spurt. The use of syntax involves a higher level of symbolism than the use of single words, because in sentences words have to relate not only to external entities, but also to one another. Morphology develops after the onset of syntax, sometime during the third year. (Rosenblith 1992) The symbolic capacity is a prerequisite for language, but it does not determine its structure or course of development. That is, once children become symbolically ready for language, they acquire it in terms of its own inherent structure and dynamics. Language ushers in a new phenomenon not foreshadowed by preceding developments.
Many researchers have emphasized, following Piaget, the continuity of language with earlier symbolic development, taking the position that language can emerge only after the symbolic capacity has been developed in infancy. (Rosenblith 1992) But there is also discontinuity in the acquisition of language, particularly in the acquisition of its grammatical aspects: syntax, morphology, and phonology. Children develop the grammar of their language to a large extent independently of their achievements in other intellectual domains. Piaget did not appreciate the autonomy of language, because he focused on words and meanings and did not concern himself with the grammatical aspects of language. Some side with Chomsky in assuming that the extent of linguistic autonomy is due to a specialized innate predisposition which unfolds without the necessary mediation of conscious intelligence. (Rosenblith 1992)
The issue of skills versus knowledge does not concern the quality of performance, but rather the processes underlying it. Discrimination and recognition can be as good or better on the sensorimotor level as on the representational level. But they are accomplished in different ways. The transition from sensorimotor to representational intelligence consists not primarily in children being able to do things better, but in their becoming thinkers and not merely doers. The child's discovery of principles and construction of rules is also evident in the shift from slow to accelerated growth, which is seen in the acquisition of vocabulary, syntax, and morphology. Thus, when one traces the acquisition of vocabulary, one sees at first small increases from week to week in the number of words uttered, and then an abrupt upturn in the rate of word acquisition. (Rosenblith 1992)
Likewise, after a period of small increments in the number of sentences, comes an explosion in syntactic productivity. A similar trend appears in the acquisition of inflections. During the slow periods, children seem to be groping to discover the operating principles, that is, that words are names, that word order can be used to express meaning, and that morphological changes can be used for semantic purposes. When a principle is discovered, it serves as a basis for the formation of generalizations and rules that can subserve a broad range of uses, thus explaining the emergent productivity. The capacity for the discovery of principles and the formation of rules has its roots in the fourth sensorimotor stage at the end of the first year, when children begin to be able to learn by inference.