The John and Ruby Lomax 1939 Southern States Recording Trip, discs 2607, 2608, 2609, 2610, 2611, 2612 & 2613. 1939. (on mp3, from the Library of Congress website)
Recordings of Mexicans in and around Brownsville, Texas. There’s a blind singer, José Suarez, whose voice is grating and guitar playing is crap. And there’s a school teacher, Manuela Longoria, whose recordings are pleasant but unremarkable, and her students.