An oral argument is given by attorneys to a judge, a panel of judges, or all the judges that belong to a court, depending on the appellate court where the case will be adjudicated and the nature of the case. This argument supplements the written argument submitted to the court via a brief, and impacts the outcome of the case. An oral argument is usually not a speech, but rather a back and forth dialogue between a judge or judges and the lawyer who is "arguing." Judges will ask questions and may challenge the lawyers on the points they present, often for the purpose of clarification on the law and its application, but sometimes to indirectly express an opinion.
In cases presented in the highest court of the land, all the judges are usually present for oral argument. In an intermediate appellate court system, a panel or single judge is often all that is required to be present for oral argument. The judges often interrupt attorneys during oral arguments, because there is a limited amount of time to clear up misconceptions and expand on some of the finer points that may have been missed or minimized in the written briefs submitted to the court. It is often possible to discern what a judge is thinking and how he or she may decide a case based on the questions asked. A skilled attorney will often pay more attention to the questions being asked than to his or her own prepared notes, and will usually try to respond persuasively.
The lawyer representing the appellant, the person who is petitioning the court to overturn the ruling of a lower court, is the first to argue the case. He often has a choice to either use the entire time to argue the case and answer questions from the judges, or reserve some of the time for a rebuttal. The lawyer representing the respondent, the person who won in the lower court, argues next and doesn't often have an opportunity to reserve time for a rebuttal. If the first lawyer has rebuttal time, he will finish the oral argument with his rebuttal. The judges can and do often ask questions during rebuttal.
Preparation for oral arguments consists of the lawyer reviewing the brief he submitted, and anticipating questions from the judges. It is not enough to anticipate the questions, but the lawyer must have answers ready to satisfy the judges and win them over. During oral arguments, the lawyer must often directly answer the question initially with a "yes" or "no" and then expound on his answers using case law and application. An effective lawyer will know when to stop arguing and leave the judge to think about the arguments he presented.