Chapter 2

Precursors to Language

The First 18 Months of Life

The Development of Linguistic Form and Function

1 Early Capacities: Birth to 2 Months

2 Early Capacities: 2 to 4 Months

3 Early Capacities: 4 to 6 Months

4 First Advances: 6 to 9 Months

5 Bringing the Strands Together: 9 to 12 Months

6 Transition to Language Use: 12 to 18 Months

Learning Mechanisms

Summary: Precursors and the Transition to Language Use

One goal for the field of language development is to arrive at an ecologically appropriate view of the infant and of the environment accessible to the developing infant brain—a brain that is in the process of maturing, learning, and integrating the various patterns or regularities to which it is exposed, including the experience of the infant's own actions and their perceptible consequences (Thelen & Smith, 1994; Campos et al., 2000). An account of infant language learning that aspires to be truly developmental should avoid predicating preformed adult-like linguistic or communicative goals for the infant. That is, there is no reason to believe that the infant is in any sense seeking to discover the structure of language or how to most efficiently communicate information, as is sometimes implied. As Locke (1993) expressed it,

Infants do not really set out to learn language. Instead, they study the movements of faces and voices—the observable displays of talkers—and gradually accommodate to and reproduce these behaviors. (p. 8)

Indeed, some see the infant as ‘innately guided’ to direct attention at first in certain biologically specified ways (Jusczyk & Bertoncini, 1988)—ways that are not, however, intrinsically linguistic. As Locke's words suggest, such ‘guided attention’ leads to noticing sound patterns, rhythms and voices familiar from experience in the womb, to riveting the gaze on caretaker faces, and to rapidly developing familiarity with other sensory experiences available from birth (e.g., the smell of their own mother's milk, familiar to an infant by 3 days of life at the latest: Macfarlane, 1975).

Arriving at a genuinely developmental account of language learning will require advances in our understanding of the nature of learning in general. As Braine (1994) pointed out, ‘the more successful a scientist is in accounting for behaviour in terms of learning, the more powerful the innate learning mechanism that they are forced to posit’ (p. 10, emphasis added). That is, if we refrain from positing innate linguistic principles (i.e., built-in knowledge of possible linguistic structures), we will need to posit, instead, learning principles that are strong enough to result in infants being able to register, represent, and creatively reproduce the complex, multilayered, hierarchical structure of any language(s) to which they may be regularly exposed in interaction with their caretakers.

There have been dramatic changes in our understanding of human learning mechanisms over the last several years (see Ellis, 1994; Saffran & Thiessen, 2003; Thiessen, 2008). In particular, research into the separable mechanisms of implicit and explicit learning and access suggests that the infant is indeed equipped with the kind of power that a non-nativist account of language learning would require, in Braine's terms. Neuroscience has played an important role in these advances, providing a far better understanding of the nature of memory, attention and learning in adults, among other things (see, for example, Squire & Alvarez, 1995; Squire & Zola, 1996; Rugg, Mark, Walla, Schloerscheidt, Birch & Allan, 1998; Baddeley, Conway & Aggleton, 2001; Ullman, 2001, 2004; Ellis, 2005; Walker, 2009). Experimental studies of infants have been an important source of new understanding as well (Rovee-Collier, 1997; Gómez & Gerken, 2000). It is likely that advances in these two lines of research will increasingly come together in coming years to flesh out an account of language acquisition that requires no innate foreknowledge of the nature of language structure.

Each child's move into language can be seen as an individual process that constructs or reconstructs the complex, multileveled system of language out of the minimal beginnings proper to a social organism, one designed to mature and learn within the context of the caretaker–child dyad. This chapter outlines what we know of the infant's unconscious and unplanned path toward intentional communication, language comprehension and speech production, with a particular focus on the emergence of linguistic form. In developing this profile we provide the newborn with only those resources that have been shown to be available at birth. In short, we start not from the basic premise that ‘all infants come into the world with linguistic skills’ (Pinker, 1994, p. 263) but instead from the working hypothesis that the ‘biological’ or instinctive component in language development is quite general, in accord with Sapir (1921, p. 4):

Walking is an inherent, biological function of man. Not so language… Speech is a non-instinctive, acquired, ‘cultural’ function.

Language, on this account, is one developmental consequence of the birth of human infants in a relatively premature state, which leads to a long period of helpless dependence on caretakers. The ‘construction’ of language by each child draws on the resources with which evolution has endowed infants and their caretakers, making human survival possible in a constantly changing environment. Our review of the developmental precursors of language includes both the biological bases and the vocal, cognitive and communicative precursors to the uniquely human ability to serve as both experiencer-listener and communicator-speaker.

Despite their seemingly obvious importance, developmental ideas have been scarce in the literature on language acquisition, which has tended to draw instead on formal models of adult language and to apply them in a deductive way to child language patterns (ch. 9). Here we sketch out the information available concerning the biological and social foundations of language development, based on both observational and experimental studies of infants, and then expand on the period in which production and perception, form and meaning all begin to come together as the child embarks on the referential or symbolic use of language. In the last section we consider some of the ideas about learning mechanisms that have emerged in the past 15 years or so, in the period that followed Braine's prescient comments.

The Development of Linguistic Form and Function

Language can be seen as emerging out of a dual biological and social foundation in step with more general cognitive abilities (Thelen & Smith, 1994; MacWhinney, 1999)—representational abilities that are unique to humans, the only species known to have developed symbol use (Deacon, 1997). The basic ‘building blocks’ of language, according to this view, are twofold:

The past quarter-century or more of empirical study of the newborn and the maturing infant has provided us with a solid foundation for tracing early development. What follows is an overview of advances that can be taken to move the child toward language learning, as schematized in Table 2.1. The table, which provides approximate chronological age ranges, is divided into three strands of development in the first 18 months, as follows:

• The strand pertaining to FUNCTION or MEANING (leftmost column) traces the route from initial social responses, broad attentional capacities and communicable needs and feelings to a developing ability to process experience and to initiate and control communicative situations (further distinguishing the ‘child as experiencer’ from the ‘child as actor’ or ‘communicator’).
• The strand pertaining to VOCAL FORM (rightmost column) traces the transformation of infant auditory biases and vocal capacities into the first recognition and production of word forms or phrases (further distinguishing the ‘child as listener’ from the ‘child as speaker’).
• The strand pertaining to LINKED FORM and FUNCTION (central column) traces the emergence of the ability to grasp verbally encoded meanings and to conceptualize them for expression (‘child as experiencer/communicator’) as well as to distinguish and recognizably reproduce conventional verbal forms (i.e., words and phrases: ‘child as listener/speaker’). These abilities can be seen to emerge from the increasing links between advances in the processing and expression of meaning, on the one hand, and the response to and production of vocal form, on the other.

Table 2.1 Bringing form and function together over the first 18 months of life: A developmental profile