studies on

[Elizabeth Bates]

I concur that things are indeed happening in the first 16 months of life
that are an important part of language acquisition!  Although a lot of
them are of the social and cognitive variety (joint attention, and so on)
that would presumably pertain to both Chinese and English in the case
of the child in question.  My comment that this doesn't strike me
as an obvious case of "L2" was simply to point out that introduction
to the 'second' language this early seems to stretch the usual definition
of "L1" and "L2".  And as the others have pointed out, matters are even
more complicated in an adoption situation when the input has switched
off in one language around the time that it switches on in the other.

Barbara Pearson has some lovely papers on the correlation between amount
of input in each of the two languages to which a "simultaneous" bilingual
child is exposed, and rate of growth in each of those languages.  With
all due respect to the important work by Hart & Risley, Huttenlocher
and others on the correlation between amount of input and progress in
language, the Pearson work really goes an important step further, because
genetic factors (confounded in most parent-child correlation studies) and
cognitive factors within the child (e.g. fast vs. slow learners) are
held constant.  Pearson's work (and that of several other people working
with early 'simultaneous' language acquisition, e.g. Virginia Marchman,
Debbie Mills and Barbara Conboy) makes it clear that, for example, an
80-20 input situation will very likely lead to an 80-20 imbalance in
the child's mastery of each language.  Indeed, the old assumption
that simultaneous bilinguals are balanced in both languages is very
clearly challenged by this work.  That's why I put the term "simultaneous"
in quotes.  Pearson's work also shows that bilingual children tend
to look as though they are falling behind in both languages, if one
examines vocabulary size separately for each language compared with
monolingual norms.  However, if one adds up all the concepts expressed
across the two languages (translation equivalents only count once),
the children growing up in a bilingual situation seem to be right on
target, compared with their age/SES matched monolingual controls.  Those
findings do, of course, give reason for optimism in the case of the
Chinese-->English child that is under discussion right now.  But, having
looked at growth curves (from other people's work) across the bilingual
cases studied to date, I still think there is reason to worry at least
enough to seek some professional advice.

BTW: it is also clear from the Spanish-English bilingual work around
here in San Diego that the input can rise and fall quite drastically
from one language to another in many more cases than you might think.
The adoption case may be an extreme version, but there is considerable
chaos in childcare arrangements and family situations of
southern California children -- babysitters come and go, grandmas
come and go, sometimes even parents come and go.  And take their
input with them. -liz bates