Bernardo Atxaga is a man whose thinking seems to be under constant review. “It is very odd to think that, in your own lifetime, your own language was forbidden,” he says, as if the thought had just occurred to him.

Atxaga is one of Europe’s and Spain’s leading novelists — the more remarkable because he writes in his native Basque, the ancient language Euskera, which the four-decades-long dictatorship of Francisco Franco tried to eradicate.

Language — or the rival claims of Basque and Catalan against Castilian Spanish — has become a lightning rod in the gathering constitutional crisis in Spain.

With Catalans pressing for secession ahead of regional elections next month and separatists certain to do well in Basque elections on Sunday, some editorialists in Madrid seem to have convinced themselves that the Spanish language, and perhaps the unity of Spain, are in mortal danger, warning of “Hispanocide.”

The writer takes a much calmer view.

Bernardo Atxaga is the pseudonym and public persona of Joseba Irazu, a private man who jealously guards his thinking space and much prefers to converse and think out loud than to be interviewed. He burst onto the literary scene in 1989 with “Obabakoak” (The People of Obaba), a collection of interlaced stories set in the Basque towns in the valleys south of San Sebastian, including Asteasu, where he grew up.

“Obabakoak” was the first work in Euskera to win Spain’s national narrative prize, and its universe has been likened to the Macondo of Gabriel Garcia Marquez’s “One Hundred Years of Solitude.” In a rare interview five years ago, Atxaga compared Obaba to the world of Virgil: “An ancient world . . . a world without Freud.”

Aside from his prodigious output of essays, short stories, poetry and children’s stories, his later novels have tended toward realism. But the Obaban universe still lurks there, along with Atxaga’s idiosyncratic take on the Basque Country: “So green outside, so dark within,” as a character observes in “Soinujolearen semea” (The Accordionist’s Son), published in 2003.

Atxaga is controversial among some Spanish nationalists for what they see as his culturally assertive Basqueness, and looked at askance by some Basque nationalists, as well. His views on Basque modern history are not exactly orthodox. Language is usually the starting point.

The Basque Country has been given different names in different periods, he points out in the course of a three-hour conversation at his home in Zalduondo. “In stable places, it is as though places have been baptized with their names — but not here.”

In the 19th century, Spain lumped the Basque Country in with neighboring Cantabria. In the 20th century, this changed to Vascongadas, a collection of provinces with Basques in them. Franco branded Vizcaya and Guipuzcoa, the two coastal Basque territories, “the traitor provinces,” because Basque nationalists had sided with the Spanish Republic against him in the 1936-39 civil war.

The late 19th-century founder of modern Basque nationalism, Sabino Arana, came up with the neologism Euzkadi, a defensively defined “Basque utopia,” Atxaga said. One radical theorist of the early ETA separatist movement coined Vasconia, an expansive concept “that reaches almost to Seville,” the novelist joked.

Atxaga has written about the transition from Euzkadi to the now more consensual Euskadi, but evidently prefers Euskal Herria, meaning “People who speak Basque.” Euskal Herria “is like a little belt on the gown of a lady,” he says.

But that is where any hint of romanticism stops. The romantic views of those such as Wilhelm von Humboldt, the 19th-century Prussian philologist who stereotyped the Basques as a mysterious people dancing in the foothills of the Pyrenees, has fueled conflict, he argues. “When you put such romantic emphasis on things, conflict becomes inevitable,” leading to “an Orwellian sense of ‘We’re from this group, and we don’t want anything to do with that other group,’ ” he said.

Atxaga says he hates ideology, once memorably describing converts as “those who as soon as they step out of one paradise manage to find another one.” He recalls the advice of his late mentor, Gabriel Aresti, the great Basque poet of the 20th century, who once told him, “You have to choose between being a writer or a purist” — by which he meant a nationalist. In more recent times, Atxaga says, years spent abroad, including in the United States, at Stanford University and in Nevada, “enabled me to think all these things through.”

Nationalists have frequently offered a vision of the Basques as rural and marginalized. “But our country is really a sprawling metropolitan region,” Atxaga said. “It’s all part of one piece of metropolitan fabric, in which each place has its local legend, but in building it you need a context, a self-image.”

Atxaga’s books have been translated into more than two dozen languages, but he will always write in Euskera. “I belong to a universe in which it was the dominant language,” he said. “What matters to me is the language, which is something as human as walking — as Aristotle said, it’s what helps us endure.”

He regards the post-Franco revival of Euskera — spoken by about 700,000 of the Basque Country’s 2.3 million people, but proportionally more among the young — as “a small miracle” that he says he never expected. “Popular resilience and the texture of community in this society has always been very strong, and that is what has saved the country.”

“If there is something that Basque society in its entirety believes, it is that they have been the target of unmeasured and systematic aggression — toward Basques, their language and their culture,” Atxaga said. “The only result has been to place Madrid at a symbolic distance of 2,500 kilometers.”