A constellation of processes found to be characteristic in the aetiology of elective mutism is explored through clinical material from the psychotherapy of a 5 year-old girl. The major factors significant in this process are excessive ties to the mother that hinder the child's social-emotional development; difficulties in discharging aggression in a situation when it is not possible to feel separate from mother; primitive ways of dealing with aggressive feelings based on phantasy and omnipotence; and - in my own experience - the symbolic equation of anus and mouth, at the developmental phase of mastery of both speech and sphincter control, as a cause of withholding words.