Continuity of Toddlers Precocious Verbal Status

1
Continuity of Toddlers Precocious Verbal
Status Deborah F. Deckner1, Lauren B. Adamson2,
Roger Bakeman2
1 Department of PsychologyClayton State
University Morrow, GA 30260
2 Department of Psychology Georgia State
University Atlanta, GA 30303
Introduction Observing children whose language
acquisition varies markedly from the typical
developmental course is a useful way to clarify
associations between earlier developing skills
and subsequent achievement. Much of the research
related to early variability has focused on
language delay and disorder rather than on
precocious language development. Thus data about
precocious language development are relatively
sparse. We sought to replicate and extend
Crain-Thoreson and Dales (1992) influential
study of precocious verbal ability and early
reading. We compared verbally-precocious and
typically-developing toddlers. First, we
described the complexity of the two groups
language during conversations with
caregivers. Second, we evaluated whether early
verbal precocity continues and predicts
differences in emergent literacy abilities. We
expected to find continuity between earlier and
later emerging linguistic skills.
Participants Participants were 72 toddlers
selected from a longitudinal study of joint
engagement. Classified as verbally-precocious
were 21 toddlers (12 girls 19 White, 2 Hispanic
mean age 24 mo, range 2226) who scored at
least 2SD above the mean on one measure of
language development or 1SD above the mean on two
measures. Another 51 toddlers classified as
typically developing (26 girls 39 White, 9
Black, 1 Hispanic, 2 other) mean age 24 mo,
range 2325) did not meet these scoring
criteria. All parents had completed high school
and the majority had completed college. Measures
were the receptive and expressive subscales of
the Mullen Scales of Early Learning and maternal
report of vocabulary size from the MacArthur CDI.
Prediction 24-month MLU contributed uniquely to
PPVT performance (R 2 .05, p lt .05), but not
emergent literacy. 24-month lexical diversity
contributed uniquely to EVT and letter knowledge,
but effects were marginally significant (R 2
.04 and .05, p .07 and .08).
Results Trajectories Hierarchical linear
modelsage nested within toddlers centered at 24
months revealed striking group differences
between 24-mo predicted values (intercepts) and
rate of change (slopes) for both MLU and lexical
diversity. Verbally-precocious vs. typically
developing toddlers had a higher mean MLU at 24
months (1.9 vs. 1.5, p .01), a steeper linear
increase (.16 vs. .12, p .01), but then a
deceleration in their rate of linear increase
(.01, p .00 no deceleration for the the
typically developing toddlerssee Figure
1). Verbally-precocious vs. typically developing
toddlers also produced more unique words at 24
months (144.1 vs. 98.9, p .00), added
significantly more unique words (15.4 vs. 12.8, p
.04) between visits, but then, again, a
deceleration in their rate of linear increase
(.50, p .04 no deceleration for the the
typically developing toddlerssee Figure
2). Differences at 42 mo Toddlers who were
classified as verbally precocious at 24 months
retained their linguistically privileged status
as preschoolers as evidenced by superior
performance at 42 months on the 1. PPVT (M
116 vs. 107, p?2 .09, p .02), 2. EVT
(M 118 vs. 110, p?2 .13, p .00), 3. the
print concepts task (M 5.3 vs. 3.6, p?2
.10, p .02), 4. but not the letter knowledge
task (M 12.2 vs. 10.2, p?2 .01, ns)
. See Figure 3.
Discussion Overall, verbally-precocious toddlers
? displayed distinctive MLU and lexical
diversity trajectories, ? remained verbally
precocious as preschoolers, and ? appeared
privileged in the develop- ment of emergent
literacy abilities. These results suggest a high
degree of stability in precocious verbal status,
with variations in language complexity during
conversations contributing to later differences
in ability. Moreover, they indicate continuity
not just in receptive and expressive language but
also to later emergent literacy. These findings
support the view that conversational
participation and practice utilizing linguistic
skills contribute uniquely to language
development, and suggest that how verbally
precocious toddlers participate in conversations
is a key ingredient in their maintaining superior
linguistic performance as preschoolers.
Figure 1

Procedures Toddlers were observed interacting
with their mothers 35 times over the course of a
year at 3 month intervals starting when the
children were, on average, 19 mo old (range
1926). At each visit, children were observed
during the Communication Play Protocol (Adamson,
Bakeman, Deckner, 2004), a semi-structured
observational protocol that encouraged the dyads
to engage in a range of communicative
contexts. Measures of mean length of utterance
(MLU) and lexical diversity (based on the number
of unique words produced) were derived for each
visit. Outcomes, assessed at 42 months, were 1.
Peabody Picture Vocabulary Test III (PPVT), 2.
Expressive Vocabulary Test (EVT), and
two measures of emergent literacy 3.
knowledge of print concepts, and4. letter
knowledge.
Figure 2
Acknowledgments This research is funded in part
by a grant from the National Institutes of Child
Health and Human Development. We thank Pamela K.
Rutherford, Janis Sayre, and Alicia Brady for
their numerous contributions throughout this
project. Presented April 2007, SRCD, Boston,
MA. Email DeborahDeckner_at_clayton.edu
Reference Adamson, L. B., Bakeman, R., Deckner,
D. F. (2004). The development of
symbol-infused joint engagement. Child
Development, 75, 11711187. Crain-Thoreson, C.,
Dale, P. S. (1992). Do early talkers become
early readers? Linguistic precocity, preschool
language, and emergent literacy. Developmental
Psychology, 28, 421-429.
Figure 3