“Trinta di Mei allowed us to recognize the subversive treasure we had in our language, which existed for centuries so we could keep secrets from the Dutch,” said Frank Martinus, 73, a Curaçaoan writer and founder of Kolegio Erasmo, a grade school where Papiamentu is the main language.

Papiamentu still has a way to go in usurping Dutch from some spheres. Curaçao’s laws are still written in Dutch. Some schools start out teaching children in Papiamentu, but then transition to Dutch, bowing to the economic opportunities the Netherlands still provide for many islanders.

Even Mr. Martinus wrote his 1973 novel “Double Play,” considered the masterpiece of modern Curaçaoan literature, in Dutch. He said that was a necessity at the time he wrote it, since he needed money fast while living in the Netherlands.

Now the novel is being translated into Papiamentu by Lucille Berry-Haseth, a Curaçaoan poet. Ms. Berry-Haseth, 73, revels in Papiamentu’s playfulness and capacity to absorb new influences, joking in an interview, for instance, that she was a “puitu killer,” or “cradle robber,” since she was a few years older than her husband. “Puitu” (pronounced poo-EE-too), she explained, came from the Spanish word “pollito,” for “little chicken” or “chick,” while “killer” came from English.

Papiamentu’s origins fascinate linguists; it emerged in a Dutch colony but its core vocabulary is a mix of Portuguese and Spanish. (Dutch Creoles crystallized elsewhere in the Dutch empire.)

Some scholars say Papiamentu evolved from a Portuguese-based lingua franca once used in West Africa, developing further in the 17th century when Curaçao was an entrepôt for South America’s slave trade and a cosmopolitan Dutch outpost settled in part by Portuguese- and Spanish-speaking Jews. Whatever its origins, Papiamentu today evokes a bit of the rhythm of Brazilian Portuguese, sprinkled with words from Dutch and English but also largely from the Spanish of Venezuela.

Papiamentu speakers frequently employ racy slang that would seem out of place in the pages of a family newspaper but not on the streets of Caracas. Moreover, many Curaçaoans are remarkably polyglot, fluently speaking Papiamentu, Dutch, English and Spanish.