Group Differences in Trajectories for Other Oral Language Measures

Listening Comprehension. Linear modelling of listening comprehension performance revealed significant progress over time, constituting an increase of 0.28 scaled scores at each subsequent time point for all children. However, disaggregation of data indicated strikingly different trajecto- ries of each group: as shown in Table 4.21, while the monolingual group plateaued in listening comprehension performance across the study, the EAL group made an average improvement of 0.50 scaled scores at each time point. Despite these different trajectories, a time × group inter- action provided only a marginally significant improvement in model fit, and was not included in the final model. As in previous analyses, a degree of nonlinearity was present in the data, such that the magnitude of the group difference remained fairly stable between t1 and t2 but decreased substantially by t3.

This pattern departs from the findings of Hutchinson et al. (2003) in which an initial mono- lingual advantage in listening comprehension increased in magnitude over time from d = 1.28 to 1.60. Similarly, results here also departed from patterns found in the three time points of Droop and Verhoeven (2003) in which a monolingual advantage in listening comprehension first increased and then decreased over time; by the end of this latter study, too, a significant monolin- gual advantage remained of between d = 0.82 and 1.13, substantially larger than effects found in the present study.

EAL: 5.63). This faster rate of progress appeared to result in convergence between the groups by t2 (from g = 0.56 to 0.21), but a slight deceleration of the EAL group at t3 served to widen this difference once more (g = 0.40). A very similar pattern was obtained using the 17 commonly attempted items only (see Tables 4.3 and 4.11).

Longitudinal studies present a rather mixed picture regarding developmental trajectories in grammatical development of mono- and bilingual comparison groups. Firstly, in agreement with results of the present study, Droop and Verhoeven (2003) found that large initial monolingual ad- vantages in morphological knowledge decreased in magnitude from Grade 3 to 4 (e.g. from d = 1.50 to 0.98 for a Turkish-Dutch comparison group, and from d = 2.34 to 1.89 for a Moroccan- Dutch group). In contrast, however, the results of Hutchinson et al. (2003) present a more equiv- ocal picture, with EAL learners between Years 2 and 4 first diverging and then converging with their monolingual peers in receptive grammar performance (TROG; a similar pattern applied here to CELF FS raw score). An interesting comparison can be made with Geva and Farnia (2012), in which the CELF-III FS subtest was administered as a measure of expressive grammar. In Grade 5 (age 10-11), the monolingual group in this study showed a modest advantage of d = 0.43, rep- resenting striking similarity with the effect found in the present study of g = 0.40. It is reported that 81% of participants in Geva and Farnia (2011) were born in the host country of Canada, and thus were likely being exposed to English from a very young age; in a similar fashion, amongst the 36 children from the EAL group who returned parental consent forms in the present study, 92% were born in England. Thus, the similarity between the two studies serves as further evidence that monolingual-bilingual group differences appear to be reduced in magnitude when bilingual learners have had a greater deal of exposure to the target language.

Summary. In terms of research question 1, group differences at t1 were apparent in both listening comprehension and expressive grammar skill, in which EAL learners tended to begin on a lower intercept than their monolingual peers. This monolingual advantage, however, was statistically significant only for expressive grammar when analysis was based upon the stimuli commonly attempted by all children. As with vocabulary measures, group differences in this study were generally smaller in magnitude than those found in the literature, and in which groups are not matched on educational experience.

Regarding research question 2, despite the fact that children with EAL started on a lower intercept than their monolingual peers in oral language measures, they did make a faster rate of progress over time, although not significantly so. Convergence between the groups was also found in listening comprehension, although reliance on standardised scores alone provides a less detailed picture of development, and the crossing of the CELF USP age threshold at t2 represented a considerable increase in difficulty for some children, potentially biasing analysis of development.

Interestingly, similar patterns emerged across vocabulary and other oral language measures: as unconstrained skills, children continued to improve in their vocabulary and grammar perfor- mance over time, with steady but gradual convergence between the two groups. Small group discrepancies in these skills present a picture in which EAL learners were more closely matched to their monolingual peers in terms of their oral English language proficiency relative to previous studies which tend to report group discrepancies of considerably larger magnitude.

4.5.3

Oral Narrative

Children’s morphosyntactic skills were assessed through an oral narrative task in which they were asked to retell a short story with the help of a picture book (Peter and the Cat). Variables included the total number of utterances, MLU in words (MLUw), lexical diversity (Root TTR), and error rate per utterance, which was divided into morphosyntactic and semantic error types. All transcripts were transcribed and analysed using CLAN (MacWhinney, 2000).