In court, lawyers speak on behalf of their clients. Criminal defendants may, however, speak for themselves in a few situations, such as when:
Defendants should prepare with their lawyers any time they are going to say anything in court. Before pleading guilty, for example, a lawyer will typically explain what to expect from the judge and how to respond. In this context, speaking in court can be just about as simple as answering a few yes/no questions.
Keep it to yourself. No matter what happens in court, you should almost never speak up without your lawyer’s consent. Otherwise, you run risks like incriminating yourself and causing the judge or jury to think less of you. Indeed, you shouldn’t speak to anyone other than your lawyer about your criminal case—at any time—unless your lawyer is present and agrees that you should talk.
For more on speaking in court and other critical considerations, see How to Behave in Court.