A person is disqualified to be a witness if the judge finds that (a) the proposed witness is incapable of expressing himself or herself concerning the matter so as to be understood by the judge and jury either directly or through interpretation by one who can understand him or her, or (b) the proposed witness is incapable of understanding the duty of a witness to tell the truth. An interpreter is subject to all the provisions of this article relating to witnesses.
K.S.A. 60-417