nput variability and the acquisition of plural morphology
Cristina Schmitt (MSU) and Karen Miller (Calvin College)
Kroch 2001 argues that the linguistic input that adults provide for children (E-language) does not always
reflect the adult grammar
(I-language) and this often results in language change, as children acquire a grammar that is slightly
different from their parents. Yang (2002, 2004) argues that the cumulative effect of input combined with a
theory of a restricted search space (UG) can explain language acquisition. Children make hypotheses
within the limits of UG that are punished or rewarded depending on their ability to account for properties of
the input. If the input is unambiguous and frequent, acquisition happens early. If the input is ambiguous,
the child may take longer to set a parameter; set a parameter incorrectly; or allow for two opposite values
of a parameter to coexist. Acquisition researchers looking at properties of the input have focused on
relative of frequency of occurrence of some grammatical feature compared to another and its effect on
acquisition. However, most of these studies departed from the idealization that the child is immerse in a
homogeneous speech community. In this paper, we provide experimental evidence supporting Kroch and
Yang's hypotheses by examining the effect of VARIABILITY in the input rather than FREQUENCY of the
input in children's developing grammars. We present three studies comparing the effect of adult variation
in plural morphology on child comprehension of plural morphology in three dialects of Spanish: Chilean
Working Class (ChWC) and Middle Class
(ChMC) and Mexican Working Class (MexWC). In the first two dialects, plural marking is variable and
comprehension only reach adult-like levels by age 7. In MexWC, plural marking is invariant, and the
acquisition facts match the English facts. We propose an acquisition model that makes use of syntactic
bootstrapping to account for the development of inflectional morphology based on data from production
and comprehension.