The van Kampen corpus is based on tapings of two Dutch girls. Laura was studied from the age of 1;9.18 to 5;10.9 and Sarah from 1;6.16 to 6;0. The child’s age at each session is given inside each file. The recordings were made roughly once or twice every month by the mother of the children (Jacqueline van Kampen). The Laura corpus exists of 72 45-minute recordings. The Sarah corpus consists of 50 45-minute recordings. The recordings were made in unstructured, regular home settings between the target child and the mother. The initial transcription is done by one of the assistants. The final version is always checked by Van Kampen. There has been no explicit use of %mor or %syn tiers. Only in the cases when the child used nonadult words or incomprehensible utterances, was the %pho tier was used. Utterances containing the tag-question marker “he” at the end have not been given a question mark. This is done to distinguish them from real questions with inversion.