We present data gathered from 130
children: 70 Polish-English bilinguals and 60 Polish monolinguals (23-36
months). The study is a part of an ongoing investigation conducted within the
framework of a Polish BI-SLI-PL project (http://www.psychologia.pl/
bi-sli-pl ) and COST Action IS0804
– WG3. Our project aims at assessing cognitive and linguistic development of
Polish bilingual children in the UK and Ireland. In the current study, parents
of bilingual children were asked to fill the CDI forms (Polish adaptation
of the Communicative Development
Inventory, Smoczyńska, 1999) as well as a detailed Parental Questionnaire
prepared by the WG3 of the COST Action IS0804 (Gatt, O’Toole, Haman, 2011).
Variables such as age, gender, type of exposure (simultaneous vs sequential),
age of exposure to English, language input (% of Polish & English), and SES
were controlled for. We report the preliminary results obtained for children
who had both parts (the lexical and grammatical) of the Polish CDI forms filled in. The results indicate
that monolingual children (MoL) outperformed bilingual children (BiL) in scores
obtained for grammatical and lexical skills. The difference was statistically
significant: Lexical part (t = 5,24; p < 0,001): MoL: M = 0,61, SD = 0,28; BiL:
M = 0,35, SD = 0,28) and grammar (t = 5,18; p < 0,001): MoL: M = 0,61, SD =
0,24; BiL: M = 0,37, SD = 0,28. There
was also an effect of gender: girls (monolingual and bilingual) had
significantly higher scores than boys in lexical and grammar part. There was high correlation between grammar
and lexicon (Pearson correlations: rMoL = 0,85, rBiL =
0,75). The results support the call for more accurate assessment of language
development of bilingual children We should interpret the data with caution
since the adaptation used in the study was designed for monolingual population
and there is a great need for tools designed especially for bilingual
population (Thordardottir, 2005; De Houwer, 2009). It is true that bilinguals
do perform differently than monolinguals but we cannot state that their
development is retarded.