An accused person's right to legal representation can only be validly waived if the waiver is fully informed, meaning the accused must have complete knowledge of the right being abandoned and the consequences of not exercising it. The state bears the burden of proving that an accused made an informed waiver. Where an accused initially indicates a desire for legal representation and subsequently appears to have changed position, the court must inquire into the circumstances of the change before accepting that the right has been waived. In serious criminal cases, particularly those involving prescribed minimum sentences or potential for substantial injustice, presiding judicial officers must not only inform unrepresented accused persons of their right to legal representation but must actively encourage them to exercise that right, explain the seriousness of the charges, and inform them of their right to state-funded legal assistance. Such explanation must be recorded with sufficient particularity to enable a determination of its adequacy, and must occur before the commencement of trial (i.e., before plea). The failure to properly inform an accused of the right to legal representation and ensure informed waiver constitutes a material irregularity. Whether such irregularity vitiates the conviction depends on whether it prejudiced the accused in the presentation of their case, which must be assessed by examining the totality of the trial proceedings.