German Vowel Contrast Discrimination by Turkish–German Bilingual Preschool Children: Effects of Age, Language Status, and Type of Bilingualism

Although bilingual vowel perception has received great interest in the past, surprisingly few studies have focused on preschool children. To shed light on this understudied age group, the present study investigated 5- to 7-year-old Turkish–German bilingual children ( n = 24), age-matched monolingual German-speaking children ( n = 26), and German-speaking adults ( n = 10), using an oddity task. The study pursues two major goals: first, we aimed to extend findings for Turkish–German bilingual school children (aged 9–12 years) to a younger group, and second, we explored potential differences related to age of onset (AoO) of German within the bilingual children (AoO of German <4 years; simultaneous bilingual children: n = 12, both languages from birth onwards; successive bilingual children: n = 12, AoO ~3;0–3;5 years). The materials included the four German vowel contrasts [ɑː]~[iː], [eː]~[ɛ], [iː]~[ɪ], and [iː]~[eː]. We predicted differences due to age (adults vs. children), language status (monolingual vs. bilingual), and vowel contrast. Furthermore, we explored potential differences by type of bilingualism (simultaneous vs. successive). The results of the Bayesian linear mixed-effects model reveal very strong evidence for age differences (adults vs. children), inconclusive evidence regarding language status (monolingual vs. bilingual), and weak evidence for the absence of differences by type of bilingualism (simultaneous vs. successive). Our results demonstrate that adult-like performance may not be expected in monolingual preschool children when explicit L1 vowel perception tasks are used. In contrast to some previous studies reporting monolingual-bilingual differences for certain vowel contrasts, the evidence for differences in vowel discrimination abilities between monolingual and bilingual preschool children in the present study remains inconclusive.