Patients having a tracheostomy tube connected to a ventilator may experience impaired quality of speech during normal operation of the ventilator. Disclosed is a breathing assistance system (10) comprising: a ventilator (12), a breathing lumen (14) arranged to communicate a flow of air between the ventilator and a tracheostomy tube (16) in the trachea of a patient, and a sensor (24) configured to generate a vibration signal representing vocal cord vibrations of the patient. The system is configured to facilitate the flow of exhaled air to the atmosphere via the upper airway of the patient in response to detection in the vibration signal of speech or attempted speech by the patient.