Juan Gelman, an Argentine poet who challenged the petty and profound tyrannies of his country’s military junta — including those directed against his family — in works that established him as a formidable presence in the Spanish-language literary canon, died on Tuesday at his home in Mexico City, where he had lived for many years. He was 83.

News reports in Mexico attributed the death to myelodysplastic syndrome, a form of bone marrow disease. However, a friend of Mr. Gelman, Iván Trejo, said the cause was lung cancer.

Mr. Gelman, the author of more than 20 books, was revered in Spain and Latin America, especially for his work in opposition to the durable far-right strain of governance in Argentina. His subjects included oppression and injustice (his ire often expressed with philosophical and linguistic vigor rather than visceral punch); the power and impotence of language; the eternalness of art, and poetry itself.

His work was not routinely translated into English, partly because he was interested in exploiting nuances of language that were difficult to capture in other tongues. In his 60s Mr. Gelman taught himself Ladino, a language of Sephardic Jews derived from Old Spanish and written in Hebrew letters. He then wrote “Dibaxu,” a book that explored the Sephardic diaspora following the Spanish Inquisition.