John Holm, a linguist who helped bring the study of creole and pidgin languages into the scholarly mainstream, died on Dec. 28 in Azeitão, Portugal. He was 72.

The cause was prostate cancer, his husband, Michael Pye, said.

While hitchhiking through Mexico and Central America as a teenager, Mr. Holm heard black Nicaraguans along the Caribbean coast speaking a non-Spanish language that seemed oddly familiar. They called it “pirate English,” a reference to its probable origin as a pidgin spoken on pirate and British Navy ships.

Although Mr. Holm could barely understand what he was hearing, it planted the seed for what would become his life’s work: the study of creole and pidgin languages spoken by millions of people around the world, especially the English-derived creoles of the Caribbean.

A pidgin is a reduced language used by groups with no language in common who need to communicate for trade or other purposes. A creole, by contrast, is a natural language developed from a mixture of different languages, like Haitian Creole, which is based on 18th-century French but absorbed elements of Portuguese, Spanish and West African languages. Semi-creole languages, which Mr. Holm also studied — Afrikaans is an example — share even more traits with their vocabulary-source languages.