For people for whom lip-reading is the only means of understanding other people, mouth masks cause problems. For many deaf people or people with severely impaired hearing, lip-reading is, in addition to sign language, an important means of communication, especially if the person they are talking to does not speak sign language.

The Federal Guild of Hearing Acousticians KdöR reports:

Social distancing and wearing a mouth and nose protection mask ensures safety and protection against infection in pandemic times. However, this is an additional challenge for people with hearing loss. Since the masks are compulsory, it has become even more difficult for hearing impaired people to understand other people. This is because the mouth/nose protection masks, which are often mandatory and have become part of everyday life for many people, influence the understanding of words spoken behind them.

This is mainly due to the filtering of high-pitched sounds by the fabric in front of the mouth. The overwhelming majority of speech sounds are located in the high frequency range, which are decisive for understanding speech. The consonants “S”, “T”, “F” and “H”, for example, belong to the high tones. Behind the mask, words such as “hand”, “sand” or “firm” and “rest” are often no longer clearly distinguishable for hearing impaired people. The brain can no longer recognise words when only vowels that belong to the low frequencies arrive. In addition, wearing masks makes it practically impossible to read facial expressions or lips.

Although it is generally possible for hearing impaired people to remove the mask or to be exempted from the obligation to wear a mask, this is not an unproblematic option. Finally, the mask serves to protect against infection and spread of the coronavirus. In addition, medical certificates that are exempt from the mask requirement do not have to be recognised by businesses.

Understanding and mutual consideration are therefore more important than ever. It is important to have conversations with people with hearing loss in places where there is little noise. This is because in closed rooms, with a babble of voices or background music, it is particularly difficult for people with hearing problems to concentrate on their conversation partner.

The Deutscher Gehörlosen-Bund e. V. (German Deaf Association) takes a more critical view of the topic and comments on it as follows:

“Lip-reading”, which a mask with a viewing window should make possible, plays only a very minor role for deaf people. “Lip-reading” is very strenuous and often leads to misunderstandings, because even under optimal conditions only about 30% of the spoken words or sounds can be visually perceived by means of the speaker’s lip movements – 70% must be guessed!

Many mouth movements are very similar, e.g. “mother” and “butter” or “out” and “house”. Especially in tense situations (doctor’s visit, clinic visit) it is impossible to understand everything by lip reading alone. In practice, masks with a viewing window also have the disadvantage that the windows steam up quickly due to the air we breathe. Then the mouth is hard to see anyway.

Source (in German): https://www.eu-schwerbehinderung.eu/index.php/33-aktuelles/4846-wie-gehen-gehoerlose-mit-der-maskenpflicht-um