The Whispered 'Ah' is a procedure developed by F M Alexander in order to free up his jaw, throat and vocal cords. It is simply a way of making an 'Ah' sound, on a whispered outward breath but it needs to be performed in a very specific manner, which allows the vocal mechanisms to be quite free. Alexander found it to be a powerful tool that he could use in his search to eradicate his vocal problems.
When the whispered 'Ah' is performed with a good understanding of the Alexander Technique, by someone who has developed the ability to inhibit their mis-use and to give themselves directions, it can help them strengthen their voice and improve their breathing. Because of these beneficial effects, the whispered 'Ah' has been found to be a valuable tool for vocalists and singers, who use it as a way of looking after their voice and helping their vocal mechanisms to work efficiently.
Doing the whispered 'Ah' procedure can also have a calming effect, as it can gradually deepen and slow down our breathing, also allowing our nervous system to become calmer. Another type of application for the whispered 'Ah' is for people to use it when stressed, whilst stuck in traffic jams for instance. By quietly sitting and releasing their jaws in this way, people can avoid the pattern that one can see so often in frustrated drivers, who clench their jaws, grind their teeth and become more and more tense. Using the whispered 'Ah' like this, is a good way to help oneself avoid tension headaches, plus drive more comfortably and safely.
You can also read how it can be useful to use whispered ah during childbirth.