John Francis planned to hold his vow of silence for one day. Instead, it lasted 17 years.

It started as a way to stop arguing about his other vow: to never ride in a car again. After the 1971 San Francisco Bay oil spill, Francis decided to avoid motorized vehicles entirely.

But he kept running into people who'd tell him that his decision was foolish — that it just left more gas for others to consume.

Francis, an environmentalist, says he worried that in these disagreements he stopped appreciating different points of view.

"I would just listen just enough to think I knew what they were going to say and if I didn't believe in what I thought they might be saying, I would stop listening to them and start thinking about my defence," Francis says.

John Francis says he could have gone the rest of his life without speaking. (Becky Hale)

In 1973, his plan was to stop talking for one whole day. He liked how that felt and continued not to speak, until he found himself checking-in on whether to keep his vow or not on a yearly basis. Francis says he appreciated how much he was learning by not speaking and how people would approach him to share their private opinions and secrets.

He even managed to go through school and get a PhD throughout his vow of silence. He says it became clear he could go the rest of his life without speaking again.

Breaking the vow

Francis broke his vow on April 22, 1990, the 20th anniversary of Earth Day.

Over the previous 6,205 days, Francis says he learned that humans were as important a part of the environment as the nature that surrounds them. For him, the environment changed from being about loss of species, and habitat and pollution, to also include people and how we treat each other. But, Francis says no one really talked about that when we talked about 'the environment.' So, he decided he needed to speak out about how issues like human rights, civil rights, gender equality, economic equity factor into the environment as well.

After 17 years of not speaking, I know the importance of there being someone there to hear what you have to say. - John Francis

"How we treat each other was like our first opportunity to treat the environment in a sustainable way or even figure out what we mean when we talk about sustainability," says Francis.

Before he spoke again, Francis played the banjo to a crowd that gathered to hear his first words after all this time: "Thank you for being here."

"After 17 years of not speaking, I know the importance of there being someone there to hear what you have to say."

This story originally aired on February 25, 2018. It appears in the Out in the Open episode "Breaking Silence".