From John Humbach
Voice authentication is moving closer all the time, and not just for credit cards (24 April, p 23). What happens with people who have had a laryngectomy? I have, and I speak with the help of a Blom-Singer valve. The air passage in this valve is only about 1 millimetre diameter and it commonly becomes partly or wholly blocked, and remains so until either it clears itself, or I clear it with the help of running water and a good mirror. This means that my voice quite normally varies from a gruff, deep-pitched sound to a silly little squeak, or anything in between. What will voice authentication make of me?
Etchinghill, Kent, UK
