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Specific Language Impairment - Generative Syntax Applications
Kiara Savage

Introduction
Few of us remember how we acquired language. It just happened. Dorothy Bishop, Oxford Professor of Developmental Neuropsychology, expresses this notion: “language is so readily acquired and so universal that it is easy to forget what a complex phenomenon it is[1].” People with normal language processing and production capabilities are able to rapidly decode sounds as they are being uttered into something meaningful by integrating different types of information: phonological, lexical, semantic, syntactic, and pragmatic, etc.[5]. After decoding the message, message formation begins. For those who have language disorders, however, processing might occur more slowly or be generally impaired[2]. What follows is a discussion of a language disorder known as Specific Language Impairment (SLI) and applications of the linguistic study of generative syntax. It is critical to understand the generative syntax applications because it provides the framework used to describe and analyze language disorders[2].

Defining Specific Language Impairment
Europeans call it developmental dysphasia[3]; the term developmental language disorder is used in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (American Psychiatric Association, 1994) [3]. The disorder is more widely known as specific language impairment[3].

Specific Language Impairment is a developmental language disorder that is best characterized by its heterogeneity[2]. Competing research makes it hard to be certain about much when it comes to this disorder because there exists so much diversity in the manifestation of the impairments among people with the disorder[4]. The larger body of research posits that SLI occurs in the absence of cognitive impairments[2], physical impairments such as blindness or deafness[3], or other confounding environmental factors[3].Research has also revealed, however, deficits in symbolic play, motor skills, phonological memory, and both linguistic and non-linguistic processing[5].These findings challenge the use of the term “specific” in describing the disorder. Hulme and Snowling make the point that the term SLI is used for those whose oral language skills are below what is expected taking their nonverbal ability into account[4]. This understanding explains the conflicting research.
The profile of people with Specific Language Impairment is heterogeneous because the etiology of the disorder is still known[5].On the surface, however, the generally understood characteristic of SLI is abnormal acquisition of grammar and vocabulary and difficulty in the domain of phonology[4]. Hoff best articulates the measures used for inclusion and exclusion, “Children are included if their language skills are below the language skills expected for their age, but they are excluded if there is another explanation such as hearing loss, low nonverbal intelligence, or a diagnosis of autism. [3]”

The Grammar of SLI
Generally speaking, the language development of children with SLI follows a normal path[3]. The difference is the slower rate at which language is acquired—particularly morphology, grammar, and vocabulary[4]. The errors made by children with SLI are the same errors made by younger typically developing children[4].Most children utter their first words by age one[4]. First words of a specifically language impaired child do not usually occur until age two[4].

Children go through what is referred to as an optional infinitive stage[2]. During this stage children omit agreement (number) and tense markers that are considered necessary in adult language use[2]. Children with SLI, however, tend to display extended optional infinitive[2,4]. This means that the stage persists longer that it does for typically developing children[2]. In particular, English-speaking children with SLI have difficulty with the verb endings –ed (past tense marker) and –s (third person singular marker) [2]. It is important to note that research suggests discrepancies in these findings cross-linguistically[2]. The salience of language features such as inflection patterns also play a role[4]. The impairments of a Spanish-speaking person with SLI look different than SLI impairments associated with English-speakers who have the disorder[4]. Studies done on children with SLI who speak other languages reveal that there are instances of SLI where tense marking is considerably error-free while subject-verb agreement is impaired[2]. A wide range of research seems to corroborate the agreement-deficit account across language, age groups, and even among those who correctly mark tense[2].

List of Grammar and Vocabulary Features Affected
- Use of morphemes and word order express to meaning[4]
- Delayed morphology acquisition relative to syntactic acquisition [4]
- Agreement-deficit [2]
- Tense omission [2]
- Delayed vocabulary acquisition [4]
- Slower response time (affects wh- movement) [5]
- Blindness to syntactic-semantic features [4]
- Rule formation: Children with SLI have difficulty using regularities to form rules [3]

These deficits not absolute. It is just the case that children with SLI follow certain grammatical rules less often than age-matched, mean utterance length matched, and typically developing children [4].

sli1b.jpg
Figure 1 Source: Hoff (2009)

sli2.jpg
Figure 2 Source: Hoff (2009)

Hypotheses

Grammar-Deficit Hypothesis
Linguists working from the generative perspective posit that language is organized in modules in the brain [4]. This view complements that idea that SLI occurs independently from other cognitive disorders and that it is simply impairment in linguistic or grammatical knowledge.

Support for the G-D Hypothesis
- Widespread problems with grammatical faculties among those with SLI
- William’s Syndrome: People with WS have cognitive deficits without deficits in language [3]
- Familiar aggregation, twin studies, pedigree [4]

Challenges to the G-D Hypothesis:
- Cross-linguistic data: Impairments look difference among children with SLI who speak other language [2].
- Delay as opposed to deviance: Language development seems to follow the same course just at a slower rate [3].

Processing-Deficit Hypothesis44
Proponents of this hypothesis claim that there are impairments in processes or mechanisms that can be attributed with language difficulties displayed in children with SLI [4].

Support for the P-D Hypothesis
- Speed and capacity restraints of people with SLI [4]
- Occurrences of auditory discrimination problems among people with SLI [4]
- Occurrences of phonological memory deficits among people with SLI [4]
- Occurrences of verbal association learning deficits among people with SLI [4]

Challenges to the P-D Hypothesis
- William’s Syndrome [3]


  1. Bishop, D. V. M. (1997). Uncommon understanding. Hove: Psychology
  2. Clahsen, H. (2008). Chomskyan syntactic theory and language disorders. In M. J. Ball, M. R. Perkins, N. Müller & S. Howard (Eds.), Handbook of clinical linguistics (pp. 165) Wiley, John & Sons.
  3. Hoff, E. (2009). Specific language impairment. In Language development (4th ed., pp. 397). Belmont: Sordi, Michele.
  4. Hulme, C., & Snowling, M. J. (2009). Specific language impairment. In Developmental disorders of language learning and cognition (pp. 129) Blackwell.
  5. Marinis, T. (2008). Syntactic processing in developmental and acquired language disorders. In M. J. Ball, M. R. Perkins, N. Müller & S. Howard (Eds.), Handbook of clinical linguistics (pp. 198) Wiley, John & Sons.