All recordings are public domain.
Marx’s works: https://librivox.org/author/2426
Engels’ works: https://librivox.org/author/769
One of Lenin’s works: https://librivox.org/author/4372
You must log in or register to comment.
There’s also many recordings on YouTube that people can download for later listening using youtube-dl on computer or NewPipe on Android.
I think Marxists.org has an audiobook section too though I am not sure.