Mississippi Code Title 63. Motor Vehicles and Traffic Regulations § 63-3-707

No person shall turn a vehicle from a direct course upon a highway unless and until such movement can be made with reasonable safety and then only after giving a clearly audible signal by sounding the horn if any pedestrian may be affected by such movement or after giving an appropriate signal in the manner provided in this article in the event any other vehicle may be affected by such movement.

A signal of intention to turn right or left shall be given continuously for a reasonable distance before turning.

No person shall stop or suddenly decrease the speed of a vehicle without first giving an appropriate signal in the manner provided in this article to the driver of any vehicle immediately to the rear when there is opportunity to give such signal.