Pierre Capretz, a former French professor at Yale and a world-renowned leader in French language teaching, died in Aix-en-Provence, France on Tuesday. He was 89.

Best known as the creator of “French in Action,” a language-learning program composed of textbooks and a widely-broadcast television series, Capretz taught at Yale for nearly half a century. During his time at the University, Capretz emphasized improving pedagogy in the French Department through immersing students in everyday French conversations, according to his colleagues.

“If you look at what he created, it still ranks among the best [teaching materials] in terms of learning languages,” French professor Ruth Koizim said.

Born in 1925, Capretz grew up in France and attended the University of Paris. Four years after the end of the Second World War, Capretz arrived in Gainesville, Fla. on an army boat. The next morning, he began teaching Latin at the University of Florida, Capretz told the News in 2010.

When Capretz moved on to teaching French, he said he found that the subject was taught using dull textbooks. Creating “French in Action” was an attempt to rectify that problem, he said.

“I thought we had to change the way we were doing it, and that a better way to teach French would be to put the students in front of what I call reach French — that is, French that is used in real contexts,” Capretz said. “So that’s where the idea came from.”

Capretz moved to Yale in 1956, where he began developing “French in Action” with recordings and visual aids for his students. Attempting to immerse students in the language, Capretz took some 10,000 photographs around France.

In his early years at the University, Capretz’s colleagues said he played a major role in refocusing the French Department on teaching.

“He did an enormous job at trying to make the French department a language-teaching department,” said French emeritus professor Chuck Porter GRD ’58. “In general it was the one that would have gotten the least help from the older members of the department, who were all literature people.”

Capretz was catapulted to national attention in 1987 with the airing of the “French in Action” television series on PBS. Produced by the Boston-based PBS station WGBH, Yale and Wellesley College, the 52-episode series follows a young couple as they fall in love while travelling around France.

The romantic comedy series aimed to introduce viewers around the country to the French language in an accessible and lighthearted way, Capretz told the News in 2010. Each episode is punctuated by grammar lessons taught by Capretz.

Brigid Sullivan, the vice president at WGBH who oversaw the “French in Action” series, said the project was initially very risky because nothing like it had ever been done before. During the production of the series, she said, she “had [her] heart in her throat.”

The series was a hit, quickly gaining a cult following.

“His technique was brilliant, and translating that technique to television was a very risky venture. It was very exciting, and was pretty scary and was fabulously successful,” Sullivan said. “It became one of the most popular telecourses of all time.”

Barry Lydgate, a French professor at Wellesley College who worked with Capretz, described “French in Action” as being “like a giant internet course, except it came out before the Internet.”

Agnes Bolton, an administrative coordinator in the French Department, said that after the series, Capretz quickly became a recognizable figure in New Haven and elsewhere.

“Everyone would recognize him,” Bolton said. “People thought he was a conductor or famous chef.”

University President Peter Salovey called Capretz “a great Yale figure” on Thursday.

Capretz’s colleagues and students described him as having a complex personality, at once formal, professional and friendly.

“He was very funny, very warm, a little ceremonious but with a very great sense of humor,” Bolton said.

Alec Baum ’14, whose L1 and L2 French classes used “French in Action,” said Capretz’s dynamic personality shone through in episodes of the series.

Lydgate described his rapport with Capretz as “the most important professional relationship in my life.”

Over time, “French in Action” evolved into an increasingly extensive series of textbooks, workbooks and video supplements, which are still used by French Departments at Yale and elsewhere. French in Action is one of the top 10 highest royalty revenue-generating licenses at Yale.

“[Capretz] made a great contribution to the study of French in America,” said Emmanuel Odjo, a French instructor at Phillips Academy Andover familiar with French in Action. “There’s probably no French teacher with over a decade of experience who did not come across French in Action.”

Zach Edelman ’16, whose French classes also used “French in Action,” described it as “the best method I’ve used to learn a language.”

“I had my doubts about the immersion approach because you were immediately speaking French and I come from a more old-fashioned school of thought that you should be learning conjugations from Day 1,” Baum said. “[But] somehow the method works.”

Capretz continued teaching at Yale until 2003, after which he moved back to France. However, he continued working on a third edition of “French in Action” as well as other projects. In 2012, he attended a 25-year reunion for those involved in the PBS series.

He is survived by his children and companion, Sylvie Mathe.