"Trial of an incompetent defendant violates the due process clause of the Fourteenth Amendment to the United States Constitution and article I, section 15 of the California Constitution. Those protections are implemented by statute in California. A criminal defendant is incompetent and may not be 'tried or adjudged to punishment' if 'as a result of mental disorder or developmental disability, the defendant is unable to understand the nature of the criminal proceedings or to assist counsel in the conduct of a defense in a rational manner.' " (People v. Hayes (1999) 21 Cal.4th 1211, 1281.) Thus, "the defendant must have a '"sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding--and ... a rational as well as a factual understanding of the proceedings against him."' The focus of the inquiry is the defendant's mental capacity to understand the nature and purpose of the proceedings against him or her. The defendant's '"technical legal knowledge"' is irrelevant. " (People v. Blair (2005) 36 Cal.4th 686, 711.) "Penal Code Section 1368 mandates a competency hearing if a doubt as to a criminal defendant's competence arises during trial. That may occur if counsel informs the court that he or she believes the defendant is incompetent , or 'if during the pendency of an action and prior to judgment, a doubt arises in the mind of the judge as to the mental competence of the defendant.' " (People v. Hayes, supra, 21 Cal.4th at p. 1281.) "The evidence must indicate that defendant is incapable of comprehending the charges against him and of cooperating with counsel in his defense. A defendant is not entitled to a trial on the issue '... merely upon the statement of defense counsel that he believes the defendant is mentally incompetent.' " (People v. Dudley (1978) 81 Cal.App.3d 866, 872.) As interpreted by the Supreme Court, "once the accused has come forward with substantial evidence of incompetence to stand trial, due process requires that a full competence hearing be held as a matter of right. In that event, the trial judge has no discretion to exercise. " (People v. Welch (1999) 20 Cal.4th 701, 738.) Thus, "where the substantial evidence test is satisfied and a full competence hearing is required but the trial court fails to hold one, the judgment must be reversed. " (Ibid.) On the other hand, when the evidence before the trial court does not amount to substantial evidence, the trial court has no duty to declare a doubt as to a defendant's present competence and its decision not to do so is not an abuse of discretion. (Id. at p. 740.) "'Substantial evidence is evidence that raises a reasonable doubt about the defendant's competence to stand trial.' Evidence regarding past events that does no more than form the basis for speculation regarding possible current incompetence is not sufficient. " (People v. Hayes, supra, 21 Cal.4th at p. 1281.) "More is required than just bizarre actions or statements by the defendant to raise a doubt of competency. In addition, a reviewing court generally gives great deference to a trial court's decision whether to hold a competency hearing.... '"An appellate court is in no position to appraise a defendant's conduct in the trial court as indicating insanity, a calculated attempt to feign insanity and delay the proceedings, or sheer temper."' " (People v. Marshall (1997) 15 Cal.4th 1, 33.)