I'm nervous about a speech, can alcohol or anxiety medication help to settle my nerves?

Anxiety. This is a bad idea. Using alcohol or drugs to settle your nerves may lead to very serious problems concerning habit formation or additions. See your doctor about your anxiety and find out the cause and get proper treatment.
Performance anxiety. Propranolol can be used for performance anxiety; it can be thought of as an "anti-adrenaline" medicine and is a class of prescription medication known as beta blockers. I agree with dr. Pizzo; using alcohol and drugs to treat anxiety can lead to tragedy; see your doctor for advise specific to your case.