Age and acquisition

Participants
The sample for test round 1 included 49 monolingual (MON) and 111 bilingual children, all of whom spoke German and one “other” language that differed across children.Of these children, 37 monolingual and 103 bilingual children participated in test round 2. The bilingual children were further divided into a simultaneous bilingual (2L1) group and a group of early second language (eL2) learners of German according to their age of onset to German. The 2L1 learners had systematic contact to German and the “other” language before 24 months of age. The eL2 learners had an age of onset between 24 and 48 months of age. Background information was collected via a parental questionnaire and telephone interviews with the parents conducted in German or in the parent’s L1. All children visited a German-speaking daycare center.
Subsequent to formal parental consent, children were included in the study if they scored at a standard value of 70 or higher in the non-verbal scales of the K-ABC at 52.4 months of age (SD = 4.7), if there was no assignment to speech-language intervention, and if according to their kindergarten teachers and their parents they showed age-appropriate language development.
Table provides the participant information. Across the three groups children’s parents had a similar socio-economic background, with the exception of the fathers of the 2L1 children, who had a longer school education than the fathers of the eL2 children. Note that the majority of studies uses maternal educational background; we included information on father’s educational background for the sake of completeness. Non-verbal IQ of the monolingual and the eL2 children did not differ, but the 2L1 group had a significantly higher non-verbal IQ than both the monolingual and the eL2 group.