Cal. Evidence Code § 701 : California Evidence Code — Witnesses — Competency — Witness incapable of being understood Date: 31 Aug 2016 TEXT PDF Current through the 2016 Legislative Session (a) A person is disqualified to be a witness if he or she is: (1) Incapable of expressing himself or herself concerning the matter so as to be understood, either directly or through interpretation by one who can understand him; or (2) Incapable of understanding the duty of a witness to tell the truth. (b) In any proceeding held outside the presence of a jury, the court may reserve challenges to the competency of a witness until the conclusion of the direct examination of that witness. Ca. Evid. Code § 701