This corpus includes data from the SLI children of the GRAMAT research, carried out by Gerard Bol and Folkert Kuiken between 1984 and 1988. This research was supported by a grant from the Praeventiefonds at The Hague in the Netherlands (Nr. 28-798). The 31 Dutch normally developing children (15 male and 16 female) in this research ranged in age from 1;07.11 to 3;07.5. Sixteen children have been recorded at two moments in time so that the total number of recordings is 47. The 20 Dutch children with Down’s syndrome (10 male and 10 female) in this research ranged in age from 4;04.21 to 18;11.5. Their intelligence level determined with a Dutch adaptation of the Merrill-Palmer Preschool Performance Tests, differed from 20 to 56. Their mental age was at least 3;6 years. The 20 Dutch SLI children (5 female and 15 male) in this research ranged in age from 4;01.16 to 8;01.17. The children all lacked sufficient intellectual or physiological impairment to account for their difficulties in language production. The speech of the 20 SLI children was audiotaped at their school, while they were playing with their speech therapist in a free-play situation. One of the two investigators was present in the room of the speech therapist. From time to time the investigator participated in the conversation. From each child 100 analyzable utterances were transcribed by the investigator that had been present at the recording. After that the utterances were analyzed according to the GRAMAT framework. GRAMAT (Grammatical Analysis of Developmental Language Disorders) is a Dutch adaptation of the descriptive morphosyntacticframework used by Crystal, Fletcher and Garman (1976). The 20 Dutch hearing impaired children (11 male and 9 female) in this research ranged in age from 3;11.14 to 9;00.15. They all suffered from sensorineural or mixed hearing loss. Their hearing impairment had been diagnosed before they were 1;6 years of age. Their hearing loss differed from 40 to 85 dB pure tone average on the better ear. The cildren were of normal intelligence. The speech of the 20 hearing impaired children was audiotaped at their school, while they were playing with their speech therapist in a free-play situation. One of the two investigators was present in the room of the speech therapist. From time to time the investigator participated in the conversation. From each child 100 analyzable utterances were transcribed by the investigator that had been present at the recording.