José Luis Álvarez Enparantza (27 September 1929 – 14 January 2012), better known by his pseudonym Txillardegi, was a Basque linguist, politician, and writer.

His philosophy was based on the following points: He was also a well-known writer and linguist under the pseudonyms Larresoro, Igara and Usako.

[3] The database of the Basque scientific-intellectual community Inguma shows references to 122 products (paper, books, talks etc.)

After becoming disillusioned with the PNV, Txillardegi was one of the founders of ETA in 1959, together with a group of young nationalists and was the visible leader of the cultural branch of the movement.

In 1976 he and Iñaki Aldekoa formed a political party, the Euskal Sozialista Biltzarrea (ESB: Congreso de Socialistas Vascos, Basque Socialist Congress).

In the general elections of 2008, he announced his Senate candidacy for the Eusko Abertzale Ekintza party (Acción Nacionalista Vasca, Basque Nationalist Action) for the precinct of Guipúzcoa.