There are several activities in the educational development of young children which require them to speak aloud to a parent or teacher. High pupil-teacher ratios and modem lifestyles limit the time available for one-to-one interaction so the benefits of enabling a computer to assist in this area are significant. There are several large international research projects attempting to implement customised systems with the aim of becoming automated reading tutors within the next few years. This thesis considers a different approach; it tests the feasibility of using commercial speech recognition technology with young children. Commercial technology has the advantage of being available now and it has matured enough for standards to have been developed which enable a speech application to easily use alternative recognition technologies if required. Recognition accuracy needs to be measurable; to simplify and disambiguate the measurement of recognition accuracy, a new metric has been developed. Improvements in recognition accuracy have been found through experimentation. The experiments need a large amount of speech data from children. To facilitate this, a set of tools has been developed to collect a speech corpus from three different regions of the country then automatically measure the recognition effectiveness under different test conditions. Speech recognition is one of several input modes which support a multimodal interface; for it to be effective, the interface with which it is integrated also needs to be effective, so this thesis additionally studies the area of Child-Computer Interaction; one of the outcomes of this study is a set of interface design guidelines which have been developed through the implementation and evaluation of several multimedia applications. Several user evaluation methods have been used to test the applications with young children in the classroom and their effectiveness is discussed. The thesis integrates the speech recognition and Child-Computer Interaction studies to produce a speech-enabled application using the developed interface design guidelines and proposed speech interface design guidelines. The application was evaluated in the classroom with very encouraging results. The thesis concludes that commercial speech recognition can be used effectively with young children if the limitations, optimisations and guidelines developed during this project are considered.