José Luis Álvarez Enparantza (27 September 1929 – 14 January 2012) was a Basque linguist, politician and writer. When writing he used the pseudonym Txillardegi. He was born in Donostia, which is called "San Sebastian" in Spanish. Even though he did not learn the Basque language until he was 17, he came to be seen as one of the most influential figures in Basque nationalism and culture in the second half of the 20th century.