In fact, if you talk about it you may reduce the risk of suicide. The risk of suicide becomes higher the more specific and available and lethal the plan. A plan for a specific time, place, and method is high risk. Risk is higher if the person has the means available or easily accessible. Risk is higher if the method is more dangerous, rapid-acting, or irreversible.
Risk is high if consciousness is clouded by alcohol or other drugs.
Those who have made previous suicide attempts are at higher risk. Ask specific questions to bet this information. Many suicides can be prevented. Most people do not want to die but want some relief from pain and problems which seem to have no solution. To intervene you must acknowledge the pain and also instill hope that the problem can be solved.