TV Dress Code for Believers

Why do some Muslim women cover their mouth? I am certainly not the right person to find an answer to this question but I found some help in the Quran (Sura 24:31) which explains the dress code for believers:

[24:31] 'And tell the believing women to subdue their eyes, and maintain their chastity. They shall not reveal any parts of their bodies, except that which is necessary. They shall cover their chests, and shall not relax this code in the presence of other than their husbands, their fathers, the fathers of their husbands, their sons, the sons of their husbands, their brothers, the sons of their brothers, the sons of their sisters, other women, the male servants or employees whose sexual drive has been nullified, or the children who have not reached puberty. They shall not strike their feet when they walk in order to shake and reveal certain details of their bodies. All of you shall repent to GOD, O you believers, that you may succeed'.

Correct me, if I am wrong, but to me these words tell me that women ‘shall not reveal any parts of their bodies, except that which is necessary’. In my understanding, when people talk the mouth must be visible because if you cover the mouth you would exclude the understanding of the deaf, therefore the mouth should never be covered since it is necessary (especially when people want to understand what is being said while watching TV). You might want to cover your nose if you can still breathe but not your mouth. I hope that this also nullifies the sexual drives of all male servants and all the other males in our expanded while globally watched households.

Photo from January 2007 of Haq TV, 'the most comprehensive Islamic channel keeping viewers in touch with the modern dynamics of islam (...)'.