Incorrect production of intonation contours is a common phonatory problem in prelingually, profoundly deaf speakers. To help deaf speakers improve this, a visual display system for teaching intonation has been developed. In this system, called the Intonation Meter, visual feedback of intonation is given as a continuous representation of the pitch contour containing only the perceptually relevant aspects of the intonation pattern. This pitch-contour representation is supposed to facilitate the interpretation of the visual feedback of the pitch contour. A study was carried out, using a Single-Subject Design, in which subjects alternately received intonation training by means of regular methods and intonation training by means of regular methods in which also use was made of the Intonation Meter, to evaluate the effectiveness of the Intonation Meter for teaching intonation to young deaf children. Prelingually profoundly deaf children aged 6 to 7 years and 9 to 11 years participated in this study. The results showed that the 9 to 11 year old children showed most progress when the Intonation meter was used in intonation training whereas 6 to 7 year olds progressed well irrespective of whether or not the Intonation Meter was used, which is in accordance with the theory of a critical period for language learning. Alternatively, it is hypothesized that the cognitive requirements of the visual feedback might be to advanced for very young children to be helpful in learning to produce certain pitch contours.