Karen M. Smith-Lock

Background: Five‐year‐olds with specific language impairment (SLI) often struggle with mastering grammatical morphemes. It has been proposed that verbal morphology is particularly problematic in this respect. Previous research has also shown that in young typically developing children grammatical markers appear later in more phonologically challenging contexts.Aims: The main aim was to explore whether grammatical deficits in children with SLI are morphosyntactic in nature, or whether phonological factors also explain some of the variability in morpheme production. The analysis considered the effects of the same phonological factors on the production of three different morphemes: two verbal (past tense ‐ed; third‐person singular ‐s) and one nominal morpheme (possessive ‐s).Methods & Procedures: The participants were 30 children with SLI (21 boys) aged 4;6–5;11 years (mean = 5;1). The data were collected during grammar test sessions, which consisted of question/answer elicitations of target forms involving picture props. A total of 2301 items were analysed using binary logistic regression; the predictors included: (1) utterance position of the target word, (2) phonological complexity of its coda, (3) voicing of the final stem consonant, (4) syllabicity (allomorph type) and (5) participant accounting for the individual differences in the responses.Outcomes & Results: The results showed a robust effect of syllabicity on the correct morpheme production. Specifically, syllabic allomorphs (e.g., She dresses) were significantly more challenging than the segmental ones (e.g., He runs) for all three morphemes. The effects of other factors were observed only for a single morpheme: coda complexity and voicing helped explain variability in past tense production, and utterance position significantly affected children's performance with the possessive. The participant factor also had a significant effect, indicating high within‐group variability ‐ often observed in SLI population.Conclusions & Implications: The systematic effect of syllabicity across both verbal and nominal morphemes suggests morphophonological influences in the grammatical development of children with SLI that cannot be fully explained by syntactic deficits. Poorer performance in producing syllabic allomorphs can be accounted for by much lower overall frequency of these forms, and by the ‘tongue‐twisting’ effect of producing similar segments in succession, as in added [ædəd], washes [wɒʃəz]. Interestingly, the greater acoustic salience of the syllabic allomorphs (an extra syllable) does not enhance children's abilities to produce them. These findings suggest that the interconnections between different levels of language have a stronger effect on the grammatical development of children with SLI than might be expected. Allomorphy should, therefore, be taken into account when designing language assessments and speech therapy, ensuring that children receive sufficient practice with the entire set of allomorphic variants.

The treatment of children with specific language impairment was used as a means to investigate whether a single- or dual-mechanism theory best conceptualizes the acquisition of English past tense. The dual-mechanism theory proposes that regular English past-tense forms are produced via a rule-based process whereas past-tense forms of irregular verbs are stored in the lexicon. Single-mechanism theories propose that both regular and irregular past-tense verbs are stored in the lexicon. Five 5-year-olds with specific language impairment received treatment for regular past tense. The children were tested on regular past-tense production and third-person singular “s” twice before treatment and once after treatment, at eight-week intervals. Treatment consisted of one-hour play-based sessions, once weekly, for eight weeks. Crucially, treatment focused on different lexical items from those in the test. Each child demonstrated significant improvement on the untreated past-tense test items after treatment, but no improvement on the untreated third-person singular “s”. Generalization to untreated past-tense verbs could not be attributed to a frequency effect or to phonological similarity of trained and tested items. It is argued that the results are consistent with a dual-mechanism theory of past-tense inflection.

This study compared the effectiveness of a school-based treatment for expressive grammar in 5-year-olds with specific language impairment delivered in two different dose frequencies: eight sessions delivered daily over 8 consecutive school days or eight sessions delivered weekly over 8 consecutive weeks. Eighteen children received treatment daily and 13 children received treatment weekly. In both groups, treatment consisted of eight 1-hour sessions of small group activities in a classroom setting. Techniques included explicit instruction, focused stimulation, recasting, and imitation. Results were analysed at the group level and as a case series with each child as their own control in a single-subject design. The 8-weeks group showed significantly greater gain in test scores over the treatment period than in an equal time period prior to treatment, whereas the 8-days group did not (Cohen's d = 1.64 for 8-weeks group). Single-subject analyses indicated that 46% of children in the 8-week group and 17% of children in the 8-day group showed a significant treatment effect. It is concluded that expressive grammar treatment was most effective when dose frequency was weekly over 8 weeks rather than daily over 8 days for 5-year-old children with specific language impairment.

Background: Children with specific language impairment are known to struggle with expressive grammar. While some studies have shown successful intervention under laboratory conditions, there is a paucity of evidence for the effectiveness of grammar treatment in young children in community settings.Aim: To evaluate the effectiveness of a school‐based intervention programme for expressive grammar in 5‐year‐olds with specific language impairment.Method & Procedures: Thirty‐four 5‐year‐old children attending a specialized school for children with language impairment participated in the study. Nineteen children received treatment for expressive grammar (experimental group) and 15 children received a control treatment. Treatment consisted of weekly 1‐h sessions of small group activities in a classroom setting for 8 weeks. Techniques included direct instruction, focused stimulation, recasting and imitation.Outcomes & Results: Results were analysed at the group level and as a case series with each child as their own control in a single‐subject design. There was a significant difference in grammatical performance pre‐ and post‐treatment for children who received grammar treatment (Cohen's d = 1.24), but not for a group of children who received a control treatment. Further, no difference in performance was found in the equivalent time period prior to treatment, nor for an untreated target. Treatment success was more pronounced in children without articulation difficulties which interfered with their ability to produce the grammatical targets (Cohen's d = 1.66). Individual analyses indicated the treatment effect was significant for the majority of children.Conclusions & Implications: Individually targeted intervention delivered in small groups in a classroom setting was effective in improving production of expressive grammatical targets in 5‐year‐old children with specific language impairment.