What should be done if an adult is choking but can still speak or breathe?

Encouraging the person to keep coughing is the correct approach for an adult who is choking but can still speak or breathe. In this scenario, coughing is a natural and effective mechanism for expelling the object that is obstructing their airway. When a person can cough forcefully, it indicates that they are able to still breathe and their airway is not fully blocked.

Promoting continued coughing allows the person to increase the pressure in their lungs, which can help dislodge the object. It's essential to remain calm and provide reassurance while monitoring their condition closely. If their ability to cough weakens or they begin to show signs of severe distress, such as inability to speak, turn blue, or lose consciousness, then you would need to take further action, such as performing the Heimlich maneuver or calling for emergency assistance.

The other methods, while potentially helpful in other circumstances, do not appropriately address the situation at hand. For example, performing the Heimlich maneuver is unnecessary at this stage since the person can still breathe and cough. Providing back blows may not be effective at this level of obstruction, and distracting them by singing would not aid in resolving the choking hazard.