7.4. Validity of the South African MB-CDIs
7.4.2. Afrikaans
When correlating the results obtained from the object naming/identification task and the MB-CDI, a significant correlation between the two is the desired outcome as this research
study aims to work towards proving the validity of the South African MB-CDIs by setting up a task that can be used when validating these MB-CDIs. The correlation between the 25 items included in the object naming/identification task and the 25 items included in the MB-CDI only, indicated a significant correlation between the two assessments overall. The correlations for infants only indicated no correlation between the two assessments and the correlations for toddlers indicated a significant correlation between the two assessments. This suggests that if a participant performs well on the object naming/identification task, they are likely to perform well on the MB-CDI, and if a participant obtains low scores on the object naming/identification task they are likely to obtain low scores on the MB-CDI as well. This is truer for toddlers than for infants. Furthermore, the correlation between the language domains of the object naming/identification task and the entire vocabulary section of the MB-CDI indicated a significant correlation between the two assessments in terms of vocabulary. Upon analysing the correlation for infants and toddlers separately, results indicated no correlation between the assessments in terms of vocabulary for infants, and a significant correlation between the assessments in terms of vocabulary for toddlers. However, the results indicated a significant correlation between the two assessments in terms of gesture for infants only. This further suggests that if a participant is likely to perform well on the language domains of the object naming/identification task, they are likely to perform well on the entire vocabulary section of the MB-CDI. This is truer for toddlers than for infants. In addition, the findings suggest that if an infant performs well on the gesture section of the object naming/identification task, they are likely to perform well on the entire gesture section of the MB-CDI. Again, this correlation could not be made for toddlers as no gesture section is included for toddlers in the Afrikaans MB-CDI. The outcome of a significant correlation between the assessments is important in this research study as it suggests a high level of concurrent validity (Sedgwick, 2012) and is in line with previously conducted research which also set out to prove the validity of different adaptations of the MB-CDI (Thordardottir & Weismer, 1996; O’Toole & Fletcher, 2010;
Perez-Pereira & Resches, 2011; Prado et al., 2018).
Furthermore, assessing the internal consistency between items plays a vital role as it may indicate whether or not the items are measuring the domains well in the assessments and an excellent internal consistency is dictated by a Cronbach’s alpha value of above .70 (Bonnet
& Wright, 2015). A comparison of the results from the 25 items in the object naming/identification task and the 25 items in the MB-CDI only, indicated a high internal consistency for the language domains. When analysed separately, high internal consistency
was found for the receptive domain, a reliable internal consistency for the expressive domain and an internal consistency which is not satisfactory for the gesture domain. This suggests that overall, the 25 items are measured well, and that items in the receptive domain are measured better in comparison to items in the expressive domain. It further suggests that the items in the gesture domain are not measured well. Comparing the results from the object naming/
identification task and the entire vocabulary and gesture sections from the MB-CDI indicated a high internal consistency for the language domains as well. When analysed separately, a high internal consistency was found for each of the receptive, expressive and gesture domains as well. This suggests that the items are measured well overall, and for each of the domains separately. Overall, the high internal consistencies found is an indication of reliability, not only between the 25 items included in both assessments and between the object naming/identification task and the entire vocabulary and gesture sections, but always between items in the domains. However, an unsatisfactory internal consistency for the gesture domain, when analysing only the 25 items included in both assessments, is not an indication for reliability in terms of gesture. Research conducted by O’Toole and Fletcher in 2010 supports the reliability of the language domains, as the vocabulary scales in their study also demonstrated a high internal consistency, with an alpha value of 0.97. As mentioned earlier for SAE, the high scores obtained on the language domains might be accounted for by an over- estimation of language abilities by parents (O’Toole & Fletcher, 2010, p.212).
Limitations
The limitations of this study are discussed in terms of the ongoing COVID-19 pandemic, the limited research available within the South African contexts on the language acquisition of young children, and that it did not account for certain factors which may influence language acquisition.
The ongoing pandemic presented an array of challenges during the research process.
Due to the nature of the research, I was required to include human beings and to come into close physical contact with them. This accounted for a short delay in obtaining ethical approval from the Faculty of Health Sciences’ Human Research Ethics Committee at UCT. Once ethical approval was granted, I was allowed to commence participant recruitment. This was challenging as the population was generally reluctant to participate in any event, including research studies, given the risk of exposure to COVID-19. In addition, many younger children were at home during this time and were not exposed to as many unfamiliar people as they might
have been pre-COVID. This could have resulted in more hesitation than usual and reluctance in getting to know an unfamiliar person. It could also have resulted in them being shy and more withdrawn, which in turn leads to not performing well on the assessment with me in comparison to how they would in circumstances which are normal to them and in which they are surrounded by only familiar people.
Another limitation was the limited research available on language acquisition of South African languages. This meant that not only was there little to none normative data to compare the results obtained in the study to, but in addition there are no assessments available within South Africa which were standardized on the South African population. This meant that there was no assessment readily available to include in the validation of other assessments, in this case the validation of the South African MB-CDIs. Research has reported that there are numerous factors which may account for potential differences in the lexical development of young children, including but not limited to exposure, input, general surroundings and socio- economic status (Fenson et al., 1994; McLeod & Bleile, 2003; Hoff, 2003; Southwood, 2013;
Gonasillan et al., 2013). These factors as listed above were not accounted for in this research study.
Clinical recommendations
This research study which aimed to devise a protocol for use in the validation of South African MB-CDIs opens up numerous opportunities for future research. The recommendations are discussed below.
This research study produced a protocol which was used to devise an object naming/identification task to be used for six South African languages. The protocol was used in this research study to devise tasks for use with SAE and with Afrikaans. It is suggested that future research focus on adapting this protocol and further utilizing it in studies focusing on the validation of the South African MB-CDIs of the remaining four languages. In addition to this, it is suggested that future research is focused on including larger sample sizes, and that participant inclusion is refined in terms of, and takes into consideration, factors which may have an effect on the language development of young children. The large gap in the literature in terms of language acquisition of young children within South Africa was evident in this research study, as little to no normative data, to be used during the analyses process, was available for SAE and Afrikaans. The research which is available on SAE and Afrikaans was conducted on small scales and largely focuses on speech acquisition rather than language
acquisition. Speech acquisition specifically “involves … the perception and production of consonants, vowels, consonant clusters, tones, prosodic features, and phonological rules of the language(s) they speak, with the outcome of intelligible speech” (McLeod & Crowe, 2018, pg 1546), whereas language acquisition involves the ability to use these speech sounds in combination for communication purposes, which further leads to the development of vocabulary knowledge (Hoff, E. (2013). It is recommended that future research focuses on the language acquisition of young children, and that it is refined to focus on infants and toddlers separately. Given that South African is a country with 11 official languages (Government Communication and Information System, 2018/19), it is imperative that future research not only focuses on the language acquisition of monolingual speakers but also on bi- and multilingual speakers.
7.5. Chapter conclusion