This study assessed a writing program with word prediction, which completed the writing of a word and spoke it out only when there was certainty that such a word was the correct one. The assessment was carried out with a young man with multiple disabilities, who typically used a word-processing program without word prediction. The two programs were compared on the time required by the participant for writing general sentences, through a social validation assessment, and eventually a check on the participant's preference. Analysis showed the program with word prediction was significantly more effective in terms of the writing time, which was halved, and was deemed preferable by 40 raters (psychology students) involved in the social validation assessment and by the participant himself. Implications of the findings are discussed.