It uses an artificial palate connected to a machine to monitor where the tongue lands on the roof of the mouth during speech.
It then shows an image, so the user can see patterns in speech rather than relying on what they hear.
Known as electropalatography, it is to be taken into schools to map the speech of six to 12-year-olds with Down's syndrome.
It was designed by researchers at Queen Margaret University in Edinburgh, led by speech and language therapist Dr Sara Wood.
She said: "Conventional speech and language therapy relies on auditory feedback which the person with Down's syndrome cannot always use to change their speech."