Transparent facemasks and shields are costly compared with classic counterparts but could prove a boon for the deaf and hard of hearing battling to communicate in the coronavirus era.

The concept has started to take off, aided not least by Youtube tutorials or the likes of American football coach Nic Saban, who makes a point of wearing his pitchside.

Other proponents include French secretary of state for people with disabilities Sophie Cluzel, who donned a mask with a see-through section to speak in parliament, and a sign-language interpreter at a Portsmouth hospital in southern England.

As Cluzel pointed out, the transparent window facilitates communication by permitting lip-reading and showing facial expressions.

"Lip reading is a plus for me," says Vivien Laplane, born deaf and author of the French blog "Appendre à écouter" (learn to listen).

"You can imagine -- or not -- that with masks it's tougher" to understand others and make oneself understood.

A deaf Indonesian couple working as tailors on the isle of Sulawesi, make and have been selling transparent masks since April.

Without them "it is impossible for a lip-reading deaf person to understand what others are saying," says Faizah Badaruddin who, along with her husband, turns out around two dozen a day.

Such efforts are boosting communication during the COVID-19 pandemic not least for the deaf and the hard of hearing who number 70 million globally, according to the World Federation of the Deaf.

The French federation of speech therapists says that classic facemasks mean "patients find themselves deprived of the main source of the oral message: the mouth and facial expressions".

Teachers say they too like the transparent model.

Rory Burnham Pickett, a professor based in Sapporo in northern Japan, says "I know it is frustrating that my pupils don't see my mouth or facial expression. I made my own transparent mask as they are difficult to find."

Governments are taking a proactive approach and placing orders.

Authorities in Quebec have placed an order for 100,000 for distribution across the health network in the Canadian province, local media say.

The provincial APDA association for the hard of hearing made an order for 100,000 washable transparent masks through local textile company Madolaine.

"Sales are going briskly," says association director Marie-Helene Tremblay.

In the United States, private US medical firm ClearMask LLC said Tuesday it had received clearance from the Food and Drug Administration for a fully transparent surgical mask for use in hospitals and clinics but also schools, retail and hospitality settings.