This case study adds a new dimension to the discourse on the authorship issue in facilitated communication. The linguistic structure produced by a young Finnish man with severe cerebral palsy was examined. Data are based on transcripts he produced from 1993 until 1996 after facilitated communication had been introduced to him. In the data analysis, as explicit criteria for his idiosyncrasies, we used patterns typical of children acquiring Finnish as their first language and those found in normal slips of the tongue, acquired aphasia, and specific language impairment. Based on the analysis (i.e. the idiosyncrasy and agrammaticality of word-forms and sentences), we strongly suggest that his output can hardly be a product of any other speaker of Finnish, including that of his facilitators.