The major tests and methods used in language acquisition diagnosis in CLP children of 3 months to 6 years of age are described. Apart from methods for phonetic analysis, such as spectrography, emphasis is being placed on the assessment of listening by hearing and of semantic and meta-linguistic acquisition. Additional information is obtained on the motoric, cognitive and social development (for detecting any possible multiple handicaps in these areas). In this context the major problems covered in cleft palate parent groups are also pointed out. Finally, the speech therapy provided for preschool children with severe speech problems (as compared with the control group) is outlined.