This paper reports the findings of a pilot study investigating bilingual acquisition of segmental temporal patterns. The productions of two German-English bilingual children, aged 9;11 and 12;5, have been analysed with regard to voice onset time (VOT) and extrinsic vowel length. There are three conclusions to be drawn from this investigation: Firstly, there is a great deal of variation between the subjects. Secondly, bilinguals cannot be treated as two monolinguals in one person. Thirdly, the results indicate that bilingual children are aware of fine-grained variability in the linguistic input they receive, and are able to produce corresponding patterns which are, however, not identical to the adult monolingual target.
This provides further evidence in favour of the dual systems hypothesis. It is suggested that the 1/2 systems hypothesis as applied in the field of bilingual language acquisition might be misleading and monolingual and bilingual first language acquisition might result in similar cerebral representation, since within-language variation is likely to be represented by the same neurological structures as between-language variation.