In the Basque country of France is L’Abbe Cestac, a Bernardine convent of silent nuns who have voluntarily given up speech in dedication to God. They also cannot look at other humans, keeping their eyes always to the ground. Some exceptions: they are allowed to confess their sins verbally to the Bishop and to speak to friends and relatives who can visit once a year.
Founded in 1847 near Biarritz, the cloister began humbly with 16 cells made of straw on the dusty, sand dune land. In fact, one of the major contributions of the nuns was to halt the advance of the sand dunes by planting species of pine. The cemetery is an incredible sight to see, with tombs of sand which are remodeled and maintained regularly .
This 1901 article in The Strand recounts the visit of the French Emperor and Empress in 1854, one of the only times perhaps a nun removed her hood and showed her face. The article also mentions that at the time, there were 45 Silent Sisters, many from wealthy French families.
There isn’t a lot of documentation about the Silent Sisters, but a celibate, silent group of the same name does appear in Game of Thrones. Today, you can visit the convent which is open to the public every day and buy produce from their market.