The TWO Folkways LP's (now reissued as 1 CD) have booklet notes which
include texts. Available as PDF files on the Smithsonian site.
(most texts omitted in the CD booklet).
http://www.folkways.si.edu/search/?query=spanish+civil+war

BEAR FAMILY issued a massive collection of Spanish Civil War recordings
Espana en el Corazon.
https://www.bear-family.com/various-history-spanien-im-herzen-lieder-des-spanischen-buergerkrieges-7-cd-1-dvd-box.html

Thomas.