Except as otherwise provided by law, every person is competent to be a witness.
Md. R. Evid. 5-601
This Rule is derived from F.R.Ev. 601.
Committee note: Under this Rule, a witness is not generally incompetent by virtue of status. A court could find, however, that because of insufficient memory, intelligence, or ability to express oneself, or inability to appreciate the need to tell the truth, a particular witness is not competent to testify as to certain matters. See Rules 5-401 through 5-403, and 5-603.
Code, Courts Article, §§ 9-104 and 9-116.