Second Language Acquisition and Second Language Learning

correlations between structural complexity of caretaker speech, and linquistic maturity in children. Some sample correlations are presented in Table 2.

                Table 2. Degree of fine-tuning in caretaker speech
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                                     Child language variables
Input characteristics __________________________________________________
                       VP aux.^a  NP infl.^a  MLU^a  MLU^b  compr.^b  age^b
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S-node/utterance         0.21      -0.05    0.37  0.30   0.55^*   0.36
MLU                      0.34       0.10    0.37  0.56^*  0.75⁺   0.51^*
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a: Newport, Gleitman, and Gleitman, 1977.
b: Cross, 1977.

Key:
VP aux. = auxiliaries such as modals, progressive and perfective elements.
NP infl. = nominal inflections, primarily plural markers.
MLU = mean length utterance.
compr. = score on a comprehension measure (see Cross, p. 157).
age = child's age in weeks.
* = p < 0.05.
+ = p < 0.01.

The third "fact" of interest to us here is that according to scholars working in the area of child language acquisition, the relative "simplicity" of caretaker speech is probably not due to any conscious effort on the part of the caretaker to teach language. Rather, caretakers modify their speech in order to communicate with children, in order to control their behavior, in order to make them understand what they are saying. (For detailed discussion, see especially Newport et al., pp. 124-130).

These three findings lead to the following generalization concerning the relationship of input and the child's developing grammar. Children progress by understanding language that is a little beyond them. That is, if a child is at stage i, that child can progress to stage i + 1 along the "natural sequence" (where i and i + 1 may be a block of structures; more correctly the child who has just acquired the members of i can then acquire a member of i + 1) by understanding language containing i + 1. The child understands language containing structure that is a bit beyond him or her with the aid of context. The fact that caretaker

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