van der Lely H K, Rosen S, McClelland A
Department of Psychology Birkbeck College University of London, Malet Street, London, WC1E 7HX, UK.
Curr Biol. 1998 Nov 19;8(23):1253-8. doi: 10.1016/s0960-9822(07)00534-9.
Specific language impairment (SLI) is a disorder in which language acquisition is impaired in an otherwise normally developing child. SLI affects around 7% of children. The existence of a purely grammatical form of SLI has become extremely controversial because it points to the existence and innateness of a putative grammatical subsystem in the brain. Some researchers dispute the existence of a purely grammatical form of SLI. They hypothesise that SLI in children is caused by deficits in auditory and/or general cognitive processing, or social factors. There are also claims that the cognitive abilities of people with SLI have not yet been sufficiently characterised to substantiate the existence of SLI in a pure grammatical form.
We present a case study of a boy, known as AZ, with SLI. To investigate the claim for a primary grammatical impairment, we distinguish between grammatical abilities, non-grammatical language abilities and non-verbal cognitive abilities. We investigated AZ's abilities in each of these areas. AZ performed normally on auditory and cognitive tasks, yet exhibited severe grammatical impairments. This is evidence for a developmental grammatical deficit that cannot be explained as a by-product of retardation or auditory difficulties.
The case of AZ provides evidence supporting the existence of a genetically determined, specialised mechanism that is necessary for the normal development of human language.
特定语言障碍（SLI）是一种在其他方面发育正常的儿童中语言习得受损的病症。SLI影响约7%的儿童。纯粹语法形式的SLI的存在已极具争议，因为这表明大脑中存在一个假定的语法子系统且具有先天性。一些研究人员对纯粹语法形式的SLI的存在提出质疑。他们推测儿童的SLI是由听觉和/或一般认知处理缺陷或社会因素导致的。也有人声称，SLI患者的认知能力尚未得到充分表征，不足以证实纯粹语法形式的SLI的存在。
我们展示了一个患有SLI的男孩AZ的案例研究。为了研究主要语法损伤的说法，我们区分了语法能力、非语法语言能力和非语言认知能力。我们调查了AZ在这些领域的每种能力。AZ在听觉和认知任务上表现正常，但存在严重的语法损伤。这证明了一种发育性语法缺陷，不能解释为发育迟缓或听觉困难的副产品。
AZ的案例提供了证据，支持存在一种由基因决定的、对人类语言正常发育必不可少的专门机制。
