As discussed earlier, roughly-tuned caretaker speech covers the child's i + 1, but does
not focus on i + 1 exclusively. Part (3) of the input hypothesis claims that this is optimal.
Rough-tuning has the following advantages in child first language acquisition:
(1) It ensures that i + 1 is covered, with no guesswork as to just what i + 1 is for
each child. On the other hand, deliberate aim at i + 1 might miss!
(2) Roughly-tuned input will provide i + 1 for more than one child at a time, as
long as they understand what is said. Finely-tuned input, even if accurate (i.e.
even if it "hits" i + 1), will only
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