In Junot Diaz's novel, The Brief Wondrous Life Of Oscar Wao (2007), the hero, Oscar de Leon - an overweight Dominican-American nerd - turns at a dark point in his life to his beloved fantasy trilogy, J.R.R. Tolkien's The Lord Of The Rings.

But he finds himself confronted with the line "and out of Far Harad black men like half-trolls" - people who look like him painted as the villain - and Tolkien, for him, becomes the source of not solace, but heartbreak.

"The truth is, if you're on the receiving end of hegemony, there is nowhere in the dominant culture where you can be truly safe," says Diaz, who, like his hero, is a specific kind of nerd - a Caribbean immigrant nerd of African descent who "grew up in a nerd culture that loved to imagine itself entirely white".

"Even in our most beloved text, we will often find, as Oscar did, evidence of the larger culture's history of hatred of us," he adds.

Diaz, 48, won the Pulitzer Prize for Fiction and the National Book Critics Circle Award for Oscar Wao, which in 2015 was named by a group of American critics polled by BBC Culture as the best novel of the 21st century to date.

He will be in town for the 20th edition of the Singapore Writers Festival, which starts on Friday.

He was born in Santo Domingo in the Dominican Republic and moved to New Jersey in the United States when he was six years old. His fiction deals with the Dominican diaspora and the immigrant experience.

"This modern world system was not originally made for people of African descent, but we made it ours," he tells The Straits Times in an e-mail interview.

"To a point - our liberation is a work in progress. Literary fiction was not historically meant for poor people - we've made inroads into that as well.

"You learn to live with contradictions and, hopefully, you seek better, less toxic art. And perhaps, you'll even help create this art."

Oscar, who aspires to be the Dominican Tolkien, seeks to make the fantasy genre his own, just as Diaz carves a space in literary fiction for the voices of his community.

His novel is a multi-generational saga of the de Leon family - Oscar, a depressed outcast who struggles with his weight, nerdiness and penchant for unrequited love; his sister Lola, a rebellious longdistance runner; and their bitter, cancer-stricken mother Beli, whose incredible beauty as a young woman in Santo Domingo led her to tragic catastrophe.

The book dazzled critics with its witty mash-up of Dominican history and magic realism, as well as its breathlessly inventive use of argot - ghetto slang peppered with Spanish and geekspeak - often by narrator Yunior, a friend of Oscar's.

Describing the Dominican dictator Rafael Trujillo, Yunior says: "Homeboy dominated Santo Domingo like it was his very own private Mordor" (referring to the realm of the Dark Lord Sauron in The Lord Of The Rings).

Diaz says: "Language tends to contain all the structures of power of a society, but also the traditions of resistance to that power.

"For me, language is an infinitely contested site and I use the language in my books that best allows me to communicate my characters and their worlds and which helps me to underscore that endless contestation.

"Respectability and its rupture interest me a great deal as a writer as well," he adds.

"How could it not? I grew up in a fantastically conservative poor military family where appearances were everything and being seen for a thing was a lot better than actually being it."

Diaz, a creative writing professor at Massachusetts Institute of Technology and fiction editor at magazine Boston Review, is the partner of writer Marjorie Liu, who will also be at the Singapore Writers Festival.

He has also written two short story collections, Drown (1996) and This Is How You Lose Her (2012), both also starring Yunior.

By his own admission, he is a very slow writer - not helped by the fact that winning the Pulitzer has made him even more critical of his work.

"It hurts to write," he says. "I guess I should do something else, but I ain't much good at anything else. Sometimes, I think I'm just less bad at writing."

His most recent work is Islandborn, a picture book published this year about a young immigrant girl who was born in the Dominican Republic, but has no memory of it. A school assignment inspires her to start collecting stories from her family members in an attempt to picture her birthplace.

"I wrote Islandborn because my goddaughters wanted to see a book where girls like them were the protagonist," he says.

His goddaughters are now in their late 20s, but the book remains necessary. "There's certainly not enough children's books for kids of colour, for immigrant families."

Diaz was accused of being unpatriotic two years ago, after he campaigned for the rights of undocumented immigrants, mainly Haitians, in the Dominican Republic.

The Dominican Republic's consul in New York called his actions "anti-Dominican" and stripped him of an order of merit award given in 2009.

There is nothing new, says Diaz, about the anti-immigrant sentiment which the Dominican political elite mobilises in order to distract and confuse.

"The Dominican Republic is like the US - in both countries, antiimmigration politics are ascendant, but there is also a lot of resistance and a lot of good people involved in the fight for justice, and that gives me hope."

While literary interest in immigrant stories may be rising in the wake of the global refugee crisis and the furore over US President Donald Trump's immigration policies, he does not think this is reflected on bestseller lists.

"Even though I believe in literature with all my heart, I'm not sure literary culture is going to single-handedly change the hostility towards immigrants worldwide," he says.

"Only a movement can do that - majorities realising that we're in this madness together and that immigrants are not the enemy - predatory economic elites are."

A self-professed nasi lemak addict, he is looking forward to his first time in Singapore.

He adds: "Beyond the appetite, I love connecting with artists, teachers, librarians and activists and hearing what's going on in their worlds, learning what I should take away from this short visit, what news I might bring home that you wouldn't normally learn in the press."