A seemingly boundless love of education led Sister Mary William Posthauer of Amityville to learn Spanish and Swahili — and line dancing.

In her last years, as her eyesight failed, Posthauer continued to absorb knowledge: She listened to audio books, had the newspaper and religious texts read to her by a fellow nun, and learned to recognize visitors by the shapes they cast.

Posthauer, who died after a long illness June 25 at the motherhouse of the Dominican Sisters of Amityville, embodied her Catholic faith through decades as a teacher, said Mary Stanis, a volunteer at the home. Posthauer was 99.

“She spread the word of God through her being,” said Stanis, of East Elmhurst, Queens. “She didn’t tell you to go pray. ... She just did it by her way of life.”

Posthauer was one of three sisters from her family who became nuns and eventually lived together at the Dominican Sisters home.

Born Agnes Posthauer on Jan. 24, 1917, in College Point, Queens, the second of five daughters was raised there. She received her habit and took the name Sister Mary William on Aug. 15, 1935, when she was 18.

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For the next five decades, Posthauer taught Spanish and other subjects at parochial schools in Queens and later Molloy College in Rockville Centre. She also served as religious education coordinator at Our Lady of the Miraculous Medal parish in Point Lookout and as religious education instructor at St. Matthew parish in Dix Hills.

While teaching, she received bachelor’s and master’s degrees in Latin and Spanish from St. John’s University and a doctoral degree from Teachers College at Columbia University. She also studied at Fairfield University in Connecticut, Temple University in Pennsylvania and Catholic University in Valencia, Spain. In Spain, she met Peace Corps volunteers who were required to learn Swahili, so Posthauer also studied the language.

She became director of sisters studies at the Dominican Sisters of Amityville in 1988.

She began as a volunteer at Dominican Village in Amityville when the retirement community opened in 1992. There, she taught residents Spanish and line dancing, and produced a newsletter, for which she did all the photography.

Stanis, who befriended Posthauer when she became a volunteer there several years ago, said she was “very sweet and gentle” and “one of the most loving people you could have met.” Despite her accomplishments, Posthauer was not impressed by titles, Stanis said.

“She would get annoyed if I called her ‘doctor,’” she said.

Posthauer is survived by a sister, Joan.

A funeral Mass was said June 29 at St. Albert’s Chapel at Queen of the Rosary Motherhouse in Amityville, followed by burial at the sisters’ cemetery there.