The Legal Definition for a 'guardian ad litem' is a guardian appointed by the court to represent the interests of infants, the unborn, or incompetent persons in legal actions. Incompetent is 'not having the necessary skills to do something successfully'.
Ad Litem means for the purposes of a Court action and therefore distinguishes from a guardian as the Guardian Ad Litem has no control over the person or property of the person they are appointed to represent in Court.
Therefore any person who lacks the skills necessary to properly adduce a case before a Court or to speak before the Court is entitled to appoint a Guardian Ad Litem of their choosing who will as far as the Court is concerned be them in any proceeding. Appointing a Guardian on the grounds of mental health JCR116. To be a Guardian Ad Litem is not without its own risk (see 1999 JLR111).
However if you find yourself in Court and wish to be properly represented and do not wish to have a lawyer speak for you, but do not believe that you are capable of acting on your own behalf, you are free to seek the appointment of a Guardian Ad Litem to speak on your behalf,