Based on some research into early 20th century newspapers, I have come to believe that the phrase "green card" actually originated with Mexican immigrants who, based on the color of the card at that time, literally nicknamed it a "tarjeta verde," and then that got translated into English rather than vice versa. Today, I see Spanish language sources use "green card," "tarjeta verde" and "tarjeta de residencia" almost interchangeably.
I'm wondering whether, at least for some Spanish speakers, "green card" has become a sort of "loan translation" so that it's even absorbed into Spanish, similar to the way "carte blanche" is treated as English. Or it might be just a "code switch" -- used more as a switching back and forth between English and Spanish in the same sentence.
Can anyone advise me as to what they think is going on?
Thanks very much