What is a significant sign of severe airway obstruction?

The inability to speak is a significant sign of severe airway obstruction because it indicates that the airway is either completely obstructed or severely compromised. In a situation where a person cannot speak, they are unable to produce any sound due to obstruction in the airway, which is a critical concern in an emergency. This sign suggests that the individual is in a potentially life-threatening situation and requires immediate intervention.

The other signs mentioned, such as excessive coughing, may occur in less severe airway obstruction and can actually help to clear an obstruction. Rapid breathing could indicate panic or the body's response to insufficient air but does not necessarily signal a critical emergency on its own. Visible distress but still able to breathe is less severe; while it indicates discomfort and should not be overlooked, the presence of breath sounds suggests that the airway is not completely obstructed, allowing for some airflow. In summary, the inability to speak strongly indicates severe obstruction and necessitates urgent action, making it the most critical sign to recognize.