if it is not recorded in the language not known to accused u can prefer an appeal against the conviction order passed by the magistrate. it would be the good ground for u to prefer an appeal and to win the case. but it is the discretion of the sessions judge to remand the matter to the lower court for fresh trial or enquiry and once again trial has to take place before the same magistrate against whose order u preferred an appeal to the court of sessions.
if the plea recorded by the magistrate remains unchallenged certainly certainly it becomes valid evidence in other cases and it is valid till the disposal of the appeal preferred by u in the higher court. when appeal is pending against that order if the copy of the said order is used in other cases u can bring it to the notice of the court that the order has been stayed by the appellate court or the appeal is pending and so that u can avoid that order being used as evidence in other cases.
so prefer an appeal against the order passed on recording the plea and get it stayed immediately.