Hadley Pamela A, Holt Janet K
Department of Communicative Disorders, Northern Illinois University, 323 Wirtz Hall, DeKalb, IL 60115, USA.
J Speech Lang Hear Res. 2006 Oct;49(5):984-1000. doi: 10.1044/1092-4388(2006/071).
The purpose of this study was to explore individual differences in children's tense onset growth trajectories and to determine whether any within- or between-child predictors could account for these differences. Twenty-two children with expressive vocabulary abilities in the low-average to below-average range participated. Sixteen children were at risk for specific language impairment (SLI), and 6 children had low-average language abilities. Spontaneous language samples, obtained at 3-month intervals between 2;0 and 3;0, were analyzed to examine change in a cumulative productivity score for 5 tense morphemes: third person singular present, past tense, copula BE, auxiliary BE, and auxiliary DO. Hierarchical linear modeling was used to model intercept and linear growth at 30 months and quadratic growth overall. A growth model that included mean length of utterance (MLU) and MLU growth better explained within-child productivity score growth trajectories than a parallel model with vocabulary and vocabulary growth. Significant linear growth in productivity scores remained even after a control for MLU was in place. When between-child predictors were added in the final conditional model, only positive family history approached statistical significance, improving the overall estimation of the model's growth parameters. The findings support theoretical models of language acquisition that claim relative independence of tense marking from other more general aspects of vocabulary development and sentence length. The trends for family history are also consistent with proposals implicating faulty genetic mechanisms underlying developmental language disorders. Systematic use of familial risk data is recommended in future investigations examining the relationship between late-talking children and children at risk for SLI.
本研究的目的是探讨儿童时态起始增长轨迹的个体差异，并确定儿童内部或儿童之间的任何预测因素是否可以解释这些差异。22名表达性词汇能力处于低平均水平至低于平均水平的儿童参与了研究。16名儿童有特定语言障碍（SLI）风险，6名儿童语言能力为低平均水平。对在2岁至3岁期间每隔3个月获取的自发语言样本进行分析，以检查5种时态语素的累积产出得分的变化：第三人称单数现在时、过去时、系动词BE、助动词BE和助动词DO。使用分层线性模型对30个月时的截距和线性增长以及总体二次增长进行建模。与包含词汇和词汇增长的平行模型相比，一个包含平均语句长度（MLU）和MLU增长的增长模型能更好地解释儿童内部产出得分的增长轨迹。即使在对MLU进行控制之后，产出得分仍存在显著的线性增长。当在最终的条件模型中加入儿童之间的预测因素时，只有阳性家族史接近统计学显著性，改善了模型增长参数的总体估计。这些发现支持了语言习得的理论模型，该模型认为时态标记与词汇发展和句子长度的其他更一般方面相对独立。家族史的趋势也与暗示发育性语言障碍潜在遗传机制存在缺陷的提议一致。建议在未来研究晚说话儿童与SLI风险儿童之间关系的调查中系统地使用家族风险数据。
