A man that is born deaf, dumb, and blind is looked upon by the law as in the same state with an idiot he being supposed Incapable of any understanding. 1 Bl. Comm. 304. Nevertheless, a deaf and dumb person may be tried for felony if the prisoner can be made to understand by means of signs. 1 Leach, C. L. 102.
Law Dictionary – Alternative Legal Definition
No definition is requisite, as the words are sufficiently known. A person deaf and dumb is doli capax but with such persons who have not been educated, and who cannot communicate, their ideas in writing, a difficulty sometimes arises on the trial. 2. A case occurred of a woman, deaf and dumb, who was charged with a crime. She was brought to the bar, and the indictment was then read to her, and the question, in the usual form, was put, guilty or not guilty? The counsel for the prisoner then rose, and stated that he could not allow his client to plead to the indictment, until it was explained to her that she was at liberty to plead guilty or not guilty. This attempted to be done, but was found impossible, and she was discharged from the bar simpliciter. 3. A person, deaf and dumb, may be examined as a witness, provided he can be sworn, that is, if he is capable of understanding the terms of the oath, and assents to it and if, after he is sworn, he can convey his ideas, with or without an interpreter, to the court and jury. Phil., Ev. 14.