Mandar -vs- Enviar
Some of my resources teach "mandar" as "to send", and others teach "enviar".
Is there a difference or are they interchangeable?
I've seen both:
Voy a mandar las cartas.
Voy a enviar las cartas.
In the sense of sending something or someone, I think they are the same, but "mandar" also means to command, to give orders, to give people instructions...
Enviar comes form Latin inviare (ir- + via), which means to put on its way (-> via). Think of English "envoy". "Mandar" comes ultimately from Latin manus (hand), being something like putting something in someone's hands. Think of English "mandatory", "demand", "command", "mandate"...